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what is the go with this? is my d70 sick, or is this common? i should pursue this as warranty I'd think .. (if not then the statement that this camera can do "long" photos is completely false.)

What exactily is it about these images you are concerned about?

they look like long exposures where someone has a torch or some light source moving around etc.

I'm probably missing something

I think he is refering to the purple at the top of the image...
Did you block the viewfinder? there is a little thing to do it...

There is a small amount of light leakage around the flip mirror

I assume you are concerned with the pinkish cast in the upper left hand corner.

Have you seen anything similar on any other shots?

Have you been able to reproduce the effect with a similar time exposure?

first time ive done bulb so hadnt noticed it before

didnt cover viewfinder, but all notes ive read about "purple tinges" is that its due to amplifier heating from the CCD, something considered a fault?

I am running a bulb shot as we speak, in a dark room, under several pillows.

Some on Dpreview have said that turning on NR will alleviate it (sounds weird.) ... what are your thoughts?

anyone else have this problem with shots?

when you say there is leakage around the flip mirror, do you mean that any light entering the viewfinder may get down to the ccd during a long shot?

30 seconds, in the late afternoon just after sun down, noticeable there also ;

482 seconds ina pitch black environment. No NR.

doing the same test in a moment with NR turned on to see if it fixes it. (dpreview folk tell me it does.)

having NR turned on kills this problem completely, in the test I just did.

I wonder however if that means any information in that part of the photo will be blanked out / missing ? Or is NR a bit smarter than that?

No cause for concern Darb, my one does that as well. It's supposed to be normal. This is one of the weaknesses of using a charged couple device as an imaging sensor. Also why one should use long exposure noise reduction for exposures exceeding 1 second as recommended by the D70 manual on page 107.

Just for fun, you can turn up the signal gain (aka ISO) and the purple corner will appear with much slower exposures. 180 seconds at 1600 ISO was enough on mine to be prominent. Knowing this - it would also suggest that if you intended to shoot long exposures, lower your ISO to prolong the shutter speeds before this problem becomes apparent.

No cause for concern. It's normal. Technological limitation this day in age...

Hi Darb,
It's the nature of the CCD and D70 same as on the D100, I got the same of your feeling with my D100 two years ago, I did a test in bulb and produced a "romantic" pink. Wonder why? and Maxwell explained to me that day. That why Nikon recommended to use AC adapter to clean the CCD not set it up in Bulb as we normally did for preserve the long life of CCD.
And the pink romantic colour did not produce on D2h cos it has the difference sensor, though Nikon still not recommend to do cleaning by bulb mode as well

I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

gstark wrote:I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

What my thought was:

- He wanted to try the maximum ability of his camera in bulb mode, 482 second is 8 min. it's enough to overcook a standard piece of scoth fillet steak over the bbq on high heat.

but perhaps there's an unknown abuse to his baby and it'll suffer in the long run, the life of the CCD in his camera will be short at the end.

That what I think (once again) Nikon's well known about using "Bulb" mode to clean CCD might decrease the expectancy life of its CCD or it can be burned if there's an often misused.

Birddog114 wrote:That what I think (once again) Nikon's well known about using "Bulb" mode to clean CCD might decrease the expectancy life of its CCD or it can be burned if there's an often misused.

That's a whole different issue.

While in bulb mode, your CCD will be charged, and thus will be more difficult to clean. I know that you're directly accessing the CCD when cleaning it, but I suspect that the charge that builds up on the CCD might transfer to the AA filter.

gstark wrote:I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

if you followed the thread you'd know.

As for the practicalilty of a bulb shot, see the two posted actual campsite photos i piosted. They were 200 seconds + and i wanted it that long for a nice effect.

I quite often do 30 second plus (pseudo bulb) and the problem arises from about 40 seconds onward.

Turning on NR completely fixes the problem.

Birddog114 wrote:

gstark wrote:I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

What my thought was:

- He wanted to try the maximum ability of his camera in bulb mode, 482 second is 8 min. it's enough to overcook a standard piece of scoth fillet steak over the bbq on high heat.

but perhaps there's an unknown abuse to his baby and it'll suffer in the long run, the life of the CCD in his camera will be short at the end.

That what I think (once again) Nikon's well known about using "Bulb" mode to clean CCD might decrease the expectancy life of its CCD or it can be burned if there's an often misused.

the 482 second test was just me leaving it on bulb in a dark room to reproduce and test the "overheating" of the CCD / amps as per the thread progression in here.

I regularly do longer than 30 second shots (aka psuedo bulb.) and thats when CCD / amp heating starts to show through.

In real terms, id like to do exposures of this length if taking photos with night sky in them, or at a campsite such as my photos in the start of this thread, etc etc.

such as ;





Excuse my ignorance, but how does a bulb shot constitute "abuse" ?

The issue is closed, its the nature of CCD, and the NR engine onboard has fixed it. (else take a black shot with lens cap on and subtract, but a lot easier, though time consuming, to use onboard NR.)

Same length 480 second shot with NR turned on = no amp heating shown up whatsoever.

not sure how it digressed into CCD cleaning, but no thats not the issue.

Darb,

darb wrote:

gstark wrote:I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

if you followed the thread you'd know.

There's no need for you to become so defensive here. I'm not attacking you; I'm querying the validity of one aspect of the testing methodology that you've employed.

And yes, I did follow the whole thread, and I repeat my statement that a 482 second test is of no practical use. You're by all means welcome to try to prove me wrong on this point.

As for the practicalilty of a bulb shot, see the two posted actual campsite photos i piosted. They were 200 seconds + and i wanted it that long for a nice effect.

I quite often do 30 second plus (pseudo bulb) and the problem arises from about 40 seconds onward.

A bulb shot at 20 seconds, or even 120 seconds, is a far cry from one at 482 seconds.

The longest exposure I've shot, in a mere 30+ years of photography, would be around 60 seconds. Beyond that, for most subjects, the extra time that you're making your exposure for will gather very little (proportionally) extra light. Think in terms of the exposure relationships our cameras present to us and you'll understand what I'm saying here.

If the image's light surce is that subdued, then you'd be far better switching to a higher ISO sensitivity.

I'm also reminded of - in film terminology - the concept of reciprocity failure, and while what you're seeing appears o be the resut of the CCD warming up, I'm also wondering if there's not a similar phenomenon in digital photography.

Turning on NR completely fixes the problem.

Yes, I know that. That's why the feature is not just provided, but recommended.

I only defened because I detected sarcasm and taking of the high ground, a pet peave of mine. Perhaps I misinterpreted.

I guess you keep doing what you do, and I'll keep doing what I do. I guess you rely on tenure, i'll rely on experimentation, being the spring chicken that I am.

The types of things I want to shoot at night, and the effect I'm after, rely on time passing. Widening aperture or raising CCD gain will not help me. (though will induce noise.) Most comprise capturing very slow motion. I want to capture a subject, not just light.

There's no *need* to prove you wrong, photography is about personal choice, IMHO anyway.

A few examples of shots ive done, and/or want to do, that are much longer than your 60 second figure. The quality looks great to me. (and in most, the photo wouldnt even be a photo if it werent for the long exposure.) Most of these are between 5 and 20 minutes long.





3am









(excuse the edits, lots of misleading grammar.)

gstark wrote:Darb,

darb wrote:

gstark wrote:I would also add that your 482 second exposure "test" is really of no practical use whatsoever. When will you ever make such a long exposure?

if you followed the thread you'd know.

There's no need for you to become so defensive here. I'm not attacking you; I'm querying the validity of one aspect of the testing methodology that you've employed.

The 482 secodn test (aka just a long shot while i made a cup of tea and piece of toast) in a dark room under a pillow, was in reply to a question about whether light into the viewfinder was the cause or not. The longer the exposure, the greater the pink tinge, thus confirming its a heat problem, as that was originally what I wasnt even sure of.

now that i've read about CCD / amp heating etc, i now know.

Is there actually any truth into the assertion that this amp / CCD heating can damage things? I'd be quite peaved it does. FWIW, my canon cmos never does this. (but i still prefer my d70, which is jsut aswell as someoen stole my 300d )

So there ya go, that was the logic behind it.

I like the campground and the one with the old chapel or whatever it is with the stars in the background.

I read a thread once that talked about a overlapping method where you take subsequent shots of the same thing and combine them all to create the long effect (stars streaking etc). This way you control exposure of particular aspects as well as the noise that long exposures tend to produce.
It's called image stacker. Check it out. I found it on a thread of a site I use to go to called megapixel.net

http://www.tawbaware.com/maxlyons/cgi-b ... ?gallery=8

thanks for the great tip ... i have read about stacking and do intend to employ it when i have some time... then i could do multi hour shots (purists might argue its not a photo, meh!)

yeaaaaahhhh baby.

2 minutes, 45 seconds x 10 shots stacked. beautiful.

darb wrote:I only defened because I detected sarcasm and taking of the high ground, a pet peave of mine. Perhaps I misinterpreted.

While I'm certainly not averse to sarcasm - and often in very large chunks, in this case you misinterpreted.

Taking the high ground? No, not really; taking an experienced, well tried route? Yes, probably

I guess you keep doing what you do, and I'll keep doing what I do. I guess you rely on tenure, i'll rely on experimentation, being the spring chicken that I am.

So, do you really think you know and understand the types of photos I've taken in my 30+ years behind a lens? Do you really believe that, for me, the experimentation with (or without) a lens has stopped?

The types of things I want to shoot at night, and the effect I'm after, rely on time passing. Widening aperture or raising CCD gain will not help me.

And I accept this, with respect to certain subjects. But not to, for instance, your nighttime campground shots. Which you admit were not taken with an exposure that even began to approach 482 seconds!

(though will induce noise.) Most comprise capturing very slow motion. I want to capture a subject, not just light.

Yep. I accept this.

There's no *need* to prove you wrong, photography is about personal choice, IMHO anyway.

Well, you seemed to - vehemently - doubt my observation regarding your test. You can choose to accept my observation, or reject it; it bothers me not.

A few examples of shots ive done, and/or want to do, that are much longer than your 60 second figure. The quality looks great to me. (and in most, the photo wouldnt even be a photo if it werent for the long exposure.) Most of these are between 5 and 20 minutes long.

And there are many fine images there. I'll happily accept that some of those could well have made use of exposures well in excess of the times we're discussing.

darb wrote:The 482 secodn test (aka just a long shot while i made a cup of tea and piece of toast) in a dark room under a pillow, was in reply to a question about whether light into the viewfinder was the cause or not. The longer the exposure, the greater the pink tinge, thus confirming its a heat problem, as that was originally what I wasnt even sure of.

Ok, that answers the time question (as to why 482 seconds) and, if you were comparing it with a similar test of a shorter duration, it provides some scope for that particular test.

It doesn't change my opinion though, that, as a general (standalone) test, it has little practical value.

Is there actually any truth into the assertion that this amp / CCD heating can damage things? I'd be quite peaved it does. FWIW, my canon cmos never does this.

Actually, I suspect that you probably don't know that the Canon CMOS doesn't overheat; neither do I, and I'm not exactly sure that that's what you were trying to say.

I would accept that you do know that the Canon doesn't present the purple fringing on the images though. Is that perhaps a clarification of what you were trying to say here?

As to whether the heating can damage the CCD, I really don't know. One probably needs to look to the camera's operational specs and see what is acceptable within the stated criteria, and then try to remain within them.

One other question, if I may: what mode were you shooting in? Raw or jpg? If jpg, does this also occur in raw ?

gstark wrote:

darb wrote:I only defened because I detected sarcasm and taking of the high ground, a pet peave of mine. Perhaps I misinterpreted.

While I'm certainly not averse to sarcasm - and often in very large chunks, in this case you misinterpreted.

Taking the high ground? No, not really; taking an experienced, well tried route? Yes, probably

I guess I found you're questioning on a futile point / test, followed by assertion that in 30 years experience there's no need for long exposures, a little big.

I guess you keep doing what you do, and I'll keep doing what I do. I guess you rely on tenure, i'll rely on experimentation, being the spring chicken that I am.

So, do you really think you know and understand the types of photos I've taken in my 30+ years behind a lens? Do you really believe that, for me, the experimentation with (or without) a lens has stopped?

Likewise, do you understand the photos I was trying to take, when you informed me that there's no need for anythign longer than 60 seconds, and after questioning my techniques? ... with 30 years experience, this puts you in good stead, it seemed very odd that you would say there was no room in photography for long exposures, perhaps you meant that in the context of photos that you like taking.

my apologies (as was my reply in private message.) regarding the tone

The types of things I want to shoot at night, and the effect I'm after, rely on time passing. Widening aperture or raising CCD gain will not help me.

And I accept this, with respect to certain subjects. But not to, for instance, your nighttime campground shots. Which you admit were not taken with an exposure that even began to approach 482 seconds!

249 seconds. I'd suggest its in the same bounds as the scope for my 482 second test, that being the diagnosis of my CCD heating. See previous replies on the 482 second figure. There's no reason I wouldnt have gone longer on the campground shot, except that it would have over-exposed, Fstop was a tight as it could go. You asserted that anything over 60 seconds, in 30 yearas experience, is not necessary, then clarified to say it does with certain subjects, but not my campground shots. This is where we disagree.

(though will induce noise.) Most comprise capturing very slow motion. I want to capture a subject, not just light.

Yep. I accept this.

There's no *need* to prove you wrong, photography is about personal choice, IMHO anyway.

Well, you seemed to - vehemently - doubt my observation regarding your test. You can choose to accept my observation, or reject it; it bothers me not.

The test was to prove or disprove that the length of exposure is causing overheating, thus causing the pink tinge. It was also done to disprove another theory that light was entering the viewfinder. The longer the test, the greater the pink tinge, thus proving to me it is a heating problem. (in comparison to the 249 second original shot where this problem first was noted.) Same applies, you can accept or reject my logic on it, I can see its practical purpose in the diagnostic path I was walking down. The test could well have been 300 seconds or even 249 seconds to match precisely the time of my actual real-life exposure, but i was making a cup of tea. I think we're arguing on pedantics here ... the test is just a test. The length of my exposures in real shots was the real sticking point.

A few examples of shots ive done, and/or want to do, that are much longer than your 60 second figure. The quality looks great to me. (and in most, the photo wouldnt even be a photo if it werent for the long exposure.) Most of these are between 5 and 20 minutes long.

And there are many fine images there. I'll happily accept that some of those could well have made use of exposures well in excess of the times we're discussing.

I think we're arguing for the sake of it. I just took a bit of offence to your replies, along with disagreeing with criticism of my logic, and disagree with you that there's no room for 60 second+ exposures. (which you've since clarified.) Perhaps too much time on dpreview and other "savage" forums where all the pseudo intellects are trying to out-do each other. I'm over it

gstark wrote:

darb wrote:The 482 secodn test (aka just a long shot while i made a cup of tea and piece of toast) in a dark room under a pillow, was in reply to a question about whether light into the viewfinder was the cause or not. The longer the exposure, the greater the pink tinge, thus confirming its a heat problem, as that was originally what I wasnt even sure of.

Ok, that answers the time question (as to why 482 seconds) and, if you were comparing it with a similar test of a shorter duration, it provides some scope for that particular test.

It doesn't change my opinion though, that, as a general (standalone) test, it has little practical value.

Is there actually any truth into the assertion that this amp / CCD heating can damage things? I'd be quite peaved it does. FWIW, my canon cmos never does this.

Actually, I suspect that you probably don't know that the Canon CMOS doesn't overheat; neither do I, and I'm not exactly sure that that's what you were trying to say.

I would accept that you do know that the Canon doesn't present the purple fringing on the images though. Is that perhaps a clarification of what you were trying to say here?

In the 20 and 30 minute shots ive done with my 300D, ive never seen any pink tinges around photos. To me this would illustrate that the sensor or amp next to the sensor, isnt over-heating. At a pedantic level, one could argue that it could be overheating, but that the amp is further away and the pink tinge doesnt occur. I'm told that CCD based dslr's are infinately more susceptible to heating issues. There was no alterior game plan to my comment, just a general comment in discussing the differences between different sensors. (easily miscontrued in the current climate of canon vs nikon debates.)

As to whether the heating can damage the CCD, I really don't know. One probably needs to look to the camera's operational specs and see what is acceptable within the stated criteria, and then try to remain within them.

One other question, if I may: what mode were you shooting in? Raw or jpg? If jpg, does this also occur in raw ?

Manual says you can do bulb for 30 minutes, i think, cant remember exactly. (im at the office presently.) There certainly was not warnings that using it this way would harm it.

Was shooting JPEG as i was on a camping trip with limited space. I'd suggest RAW would brandish the same result as its the same data being pulled from the CCD ... though shooting RAW would have allowed me to post process a heck of a lot better than in jpeg!

If you shoot RAW, does the NR job still run? (havent got my camera here with me so cant answer.)

I will shoot RAW if i go out to do a specific shot though, but the camping trip was just lots of mucking around.

Im still unsure if enabling the NR will mean some data is lost in that area where the pink tinge would otherwise be, or whether NR is smarter than that ? NR doubles the shot time, so stacking and shorter exposures may be a better option for me.

ps for some reason some of my reply appears inside a tabled window, then the last reply appears on its own ... ive answered in bold so please excuse my lack of knowledge with the forum paramaters for quoting etc. be sure to look in both the tabled and non tabled reply.

darb wrote:I guess I found you're questioning on a futile point / test, followed by assertion that in 30 years experience there's no need for long exposures, a little big.

One thing about me that you need to be aware of is that I'm actually very careful about the words I choose - ask Leigh about that.

I believe that what I actually said was that in 30+ years' experience, I'd never shot longer than a 60 second exposure. To infer from that that I'm saying that there's "no need for long exposures" is drawing quite a long bow, I suspect.

My statement that "Beyond that, for most subjects, the extra time that you're making your exposure for will gather very little (proportionally) extra light." remains valid, and some of the subjects that you've presented here fit right in as the exceptions that do not fall within what I'm referring to as "most subjects".

But yes, we're talking semantics here ...

Likewise, do you understand the photos I was trying to take, when you informed me that there's no need for anythign longer than 60 seconds, and after questioning my techniques? ... with 30 years experience, this puts you in good stead, it seemed very odd that you would say there was no room in photography for long exposures.

Please see my comments above regarding what I actually did say. And carefully note them where appropriate below.

my apologies (as was my reply in private message.) regarding the tone

Noted, and the apology is accepted.

There's no reason I wouldnt have gone longer on the campground shot, except that it would have over-exposed, Fstop was a tight as it could go. You asserted that anything over 60 seconds, in 30 yearas experience, is not necessary, then clarified to say it does with certain subjects, but not my campground shots. This is where we disagree.

You're saying that your f-stop was as "tight" as it could go. By "tight" you're saying that you were at minimum aperture? F32, rather than, say, 3.5. If this were the case, wouldn't opening the aperture - f16 or F11 - have given you quite a bit more scope for reducing the length of exposure time?

Perhaps too much time on dpreview and other "savage" forums where all the pseudo intellects are trying to out-do each other. I'm over it

Good. This is not DPReview, and that is neither a good nor a bad thing.

But I do however want to keep this a friendly place, but that does not mean that we cannot have a vibrant debate. Let's just remain mature people who enjoy using our cameras, and who have open minds and are willing to listen to opposing points of view.

You're saying that your f-stop was as "tight" as it could go. By "tight" you're saying that you were at minimum aperture? F32, rather than, say, 3.5. If this were the case, wouldn't opening the aperture - f16 or F11 - have given you quite a bit more scope for reducing the length of exposure time?

I was at F29 i think ... as closed as I could go. I wanted to maximise the time, I wanted to go even more than 249 seconds, but in the few previous shots I knew i'd blow the pic. I could go F40 if i was zoomed in, but wanted to maintain the wide angle.

In the campground cases, I wanted the longest possible exposure time ... which is where we disagree on technique (you'd opt for a much shorter exposure time, with lower F Stop, im surmising.

all good.

darb wrote:Manual says you can do bulb for 30 minutes, i think, cant remember exactly. (im at the office presently.) There certainly was not warnings that using it this way would harm it.

In which case I'd happily go about using it in that mode, with NR turned on.

FWIW, there's a PDF version of the manual that you can download from Nikon Asia. Might be worth grabbing a copy ...

Was shooting JPEG as i was on a camping trip with limited space. I'd suggest RAW would brandish the same result as its the same data being pulled from the CCD ... though shooting RAW would have allowed me to post process a heck of a lot better than in jpeg!

My question wasn't so much concerned about the post-processing aspects of shooting raw, but more with the purple fringing artefacts that we sometimes see on jpg images.

What you're getting doesn't really look like jpg artefacts, but I suspect that it might be an interesting extension of the testing that you're doing, to see whether or not that does have an effect on the results you're getting.

If you shoot RAW, does the NR job still run? (havent got my camera here with me so cant answer.)

I believe so.

Im still unsure if enabling the NR will mean some data is lost in that area where the pink tinge would otherwise be, or whether NR is smarter than that ? NR doubles the shot time, so stacking and shorter exposures may be a better option for me.

I believe that if you're shooting in raw, then no data is lost.

I believe that what I actually said was that in 30+ years' experience, I'd never shot longer than a 60 second exposure. To infer from that that I'm saying that there's "no need for long exposures" is drawing quite a long bow, I suspect.

With that comment, and also the questioning on my testing logic led me to believe you were asserting that long exposures simply have no place. Incorrect interpretation it would seem, similiar to your not understanding my position on the scope and logic behind my 482 second test. To make the comment in direct opposition to my own photos, led me to believe you dont shoot long exposures, period. (until you clarified.).

But I do however want to keep this a friendly place, but that does not mean that we cannot have a vibrant debate. Let's just remain mature people who enjoy using our cameras, and who have open minds and are willing to listen to opposing points of view.

Feeling is mutual, which is why I was displeased when I felt you werent being open-minded about long exposures, and also not understanding the reasoning for my long exposure lens-cap-on test.

you may still not agree with some of the above, but at least we've got to a "this is where we disagree" point of the conversation ... which is the end point most online arguments finish

gstark wrote:

darb wrote:Manual says you can do bulb for 30 minutes, i think, cant remember exactly. (im at the office presently.) There certainly was not warnings that using it this way would harm it.

In which case I'd happily go about using it in that mode, with NR turned on.

FWIW, there's a PDF version of the manual that you can download from Nikon Asia. Might be worth grabbing a copy ...

Was shooting JPEG as i was on a camping trip with limited space. I'd suggest RAW would brandish the same result as its the same data being pulled from the CCD ... though shooting RAW would have allowed me to post process a heck of a lot better than in jpeg!

My question wasn't so much concerned about the post-processing aspects of shooting raw, but more with the purple fringing artefacts that we sometimes see on jpg images.

What you're getting doesn't really look like jpg artefacts, but I suspect that it might be an interesting extension of the testing that you're doing, to see whether or not that does have an effect on the results you're getting.

If you shoot RAW, does the NR job still run? (havent got my camera here with me so cant answer.)

I believe so.

Im still unsure if enabling the NR will mean some data is lost in that area where the pink tinge would otherwise be, or whether NR is smarter than that ? NR doubles the shot time, so stacking and shorter exposures may be a better option for me.

I believe that if you're shooting in raw, then no data is lost.

Cool, i'll certainly do some more testing in that regard next time opportunity presents.

darb wrote:I was at F29 i think ... as closed as I could go. I wanted to maximise the time, I wanted to go even more than 249 seconds, but in the few previous shots I knew i'd blow the pic. I could go F40 if i was zoomed in, but wanted to maintain the wide angle.

In the campground cases, I wanted the longest possible exposure time ... which is where we disagree on technique (you'd opt for a much shorter exposure time, with lower F Stop, im surmising.

I'd go with with whatever permitted me to get the image I was after.

My suspicion is that F11 or F16, with a maximium time of 60 seconds would probably work. I'm allowing for the probability that there's going to be some elements of reciprocity failure underlying what's happening, and I'm also allowing for the possibility that the image displayed on my LCD won't always be an accurate representation of what I've shot.

What I'm curious about is what differences you are expecting to see - or did in fact see - in terms of (a) exposure and (b)the image captured, within the following constraints. And I'll talk in terms of rounded numbers here; there's no effective difference between 240 seconds and 249 seconds in terms of exposure unless some other event occurs within those 9 seconds.

F29 @ 240 seconds

F16 @120 seconds

F8 @ 60 seconds

I'd probably want to throw in a few intermediate EVs as well, to give myself a good spread of images from which to choose.

And - presuming that you used ISO 200, bumping sensitivity to 400 will lose very little in terms of quality from noise, but give you a whole extra set of values within which you could play.

Is this making any sense?

yep makes sense, had the same thought myself.

I did try various mixtures already, those 2 shots were the 2 I kept ... basically i wanted to capture as much motion as I could, as many torch lights moving around (from my friends moving around etc etc.)

I understand I could have increased ISO and understand what you mean, but my primary intention was to capture as much movement as I could. I toyed with the idea of putting a filter (polar or ND if i had one.) back on to further slow it.

I think i shot at 30 seconds, 60, 2mins, 3 mins and thereon (roughly.) ... but i really wanted to capture the whole "a night in camp" feel, the torches inside the blue tent movign around from one of the girls getting changed, etc etc. I had reservations that it might be too hard to get lots of low-light movement, and not blow the highlights ... but I cheekily hid our gas light behind a tree to get around that.

If i'd found the long exposure was causing problems (admittedly i wouldnt know this until i got home.) then id know next time that id have to compromise a bit and pull back on the exposure length or what-have-you.

I don't want to complicate the issue and am only making a contribution because I think the use of bulb is inherently interesting. In a sense it requires a thread of its own and demonstrates the beauty of this tool for experimentation. I have no view on either side here, only satisfying my curiosity on the technical issues of the D70.

If you look at http://members.cox.net/gscundiff/astro/DeepSpace.html you will see 5 minute exposures at ISO1600 in an astrophotography environment. I was actually looking for a post I read a while ago when the D70 was first released which bemoaned the fact that the D70 did not have mirror lockup for the astronomy community. It looks like they have not let that stand in the way of interesting views of the night sky.

Same Same.

As an astrophotographer i have encoutered thos problem and beaten it with NR on. The longest exposure i have done so far is 20 minutes. (40 minutes with NR on)

The noise reduction does not impinge on any stars or objects i am shooting for as they are mostly in the middle of the picture anyway. i have more problem with clouds and light pollution in Sydney than CCD heating anyway. (Considers moving to Kulgera NT)

Killakoala,

What do you use for your astro photos?
I have Meade ETX90EC, but so far my attempts at astro photography failed.
This telescope is just not stable enough - get heaps of blur from mirror slap
Great for visual observation & very portable, but SLR is bit much for it I think...

Flyer, one comment Killa made at the last meet, which I thought was brilliant and may apply to your problem, is to stick a blanket over your telescope. I assume if the slap is real bad, make it a wet blanket

Hi guys, I registered just to make a reply in this topic.

Some of the photos posted on the previous page by darb are mine, taken with a cannon 300D.

I find gstark's tone incredibly arrogant "I've got 30+ years experience ..." blah blah blah.

There are many times where a 60+s exposure is warranted. Astro is one, but there are many other times I have taken 200-500s exposures not for some experimental reason, but simply because the exposure requires it.

For example This photo ...

Taken at 2:41am from the top of Little Mt. Higginbotham at Mt. Hotham under a full moon.

Now I was trying to get an eerie "daytime" effect, but even under a full moon the exposure required was 229s, @ F/3.5 ISO100.

Now it would have been a good shot (if I had got the focus correct). In future I would have closed up the appature a bit to increase the DoF (It is a bit hard to focus correctly in pitch black ... even if you have an infinite focus mark on your lens)!

Anyway, I guess what I am saying is that, rather than your "who cares" comments, realise that there ARE good reasons why the over heating is a real problem.

FYI I have taken exposures up to 1500+s with my canon 300D and have not encountered any heating issues. And the 30min limit actually has more to do with battery life than anything else. With a battery pack you could take an unlimited exposure.

Hi Trapdoor, and welcome.

trapdoor wrote:Hi guys, I registered just to make a reply in this topic.

Some of the photos posted on the previous page by darb are mine, taken with a cannon 300D.

It's nice to know that your's. Thanx for that information.

I find gstark's tone incredibly arrogant "I've got 30+ years experience ..." blah blah blah.

You're entitled to your opinion. You happen to be wrong, but so be it. It's a simple statement of fact.

There are many times where a 60+s exposure is warranted. Astro is one, but there are many other times I have taken 200-500s exposures not for some experimental reason, but simply because the exposure requires it.

Fine. That's how you take your photos; I accept and respect that. I probably shoot under very different circumstances, and very different subjects. Sometimes, 1/4000 sec is too long an exposure.

Now, if you'd please sit back and relax, and take a few moments to reread precisely what I said, you'd understand that I said that I don't take photos that need that long an exposure. I've already explained this, and at great length.

I've also already explained, and also at great length, that long exposures such as these that you and Darb are doing are relatively uncommon. Perhaps not so rare for you, and that's fine. But in the general realm of photography, they are.

Now, given that this this aspect has already been done to death, what was your point?

Anyway, I guess what I am saying is that, rather than your "who cares" comments, realise that there ARE good reasons why the over heating is a real problem.

With respect, and as Darb readily acknowledges, if he's using the NR feature of the camera, there is no problem. It's that simple.

[/quote]FYI I have taken exposures up to 1500+s with my canon 300D and have not encountered any heating issues. And the 30min limit actually has more to do with battery life than anything else. With a battery pack you could take an unlimited exposure.[/quote]

No. With a battery back you'd be limited to the time available within the parameters of the power provided by that battery pack.

With an external mains power supply, you coupld probably take an unlimited exposure, but to what avail? what would be the point of that?

thanks for the reply trapdoor ... though it has been done to death.

Gstark : you did come across a little arrogant & condescension was percieved , and you DID assert to me that anything over 60 seconds is useless in photography, you did this when you coupled it with your "30 years in the business" information, people only do that when they want to assert theyre correct on an issue, but you've since clarified a context on your comment to state that in YOUR personal photographic arena & technique, 60 second + has no place, and you've conceeded that to others, its more than useful, even if yourself would do it differently. (ie where capturing of slow motion over a 1hr period or whatever, is the desired result, where a lower F stop or higher ISO will not assist, which I already knew.)

Alas its your site and you can go about it as you please, and we've done it to death, as you say. The irony is that you felt one of my replies were outside the bounds of decency. (well actually i agree, but i felt i was responding to precedent ) I guess its a perception problem.

back on the overheating ... if i do want to do say a "1 hour" star trail shot, id obviously probably stack lots of 60 second shots, because if i were to do say 6 x 10 minute shots, id have to have NR turned on, which then meant a 10 minute NR job gap in between each actual exposure, therefore stuffing the shot as stars would appear to 'start and stop' in the end result.

I just hope that if I were to do 60 x 1 minute (or 30 x 2 etc.) shots in a row (with no NR so as to avoid having gaps in the star trails.) that it wouldnt heat to a point where the pink tinges are clearly visible even in 30 - 60 second shots.

what do you think? pulling from your tenure, what would you suggest be the best way to achieve such a shot?

darb wrote:... if i do want to do say a "1 hour" star trail shot, id obviously probably stack lots of 60 second shots, because if i were to do say 6 x 10 minute shots, id have to have NR turned on, which then meant a 10 minute NR job gap in between each actual exposure, therefore stuffing the shot as stars would appear to 'start and stop' in the end result.

I just hope that if I were to do 60 x 1 minute (or 30 x 2 etc.) shots in a row (with no NR so as to avoid having gaps in the star trails.) that it wouldnt heat to a point where the pink tinges are clearly visible even in 30 - 60 second shots.

what do you think? pulling from your tenure, what would you suggest be the best way to achieve such a shot?

Ok ...

Good question. My initial response is that this is something that I've never had a real interest in trying, and as such, it's beyond the realms of my personal experience.

You're quite correct that executing a series of shots with NR, thus giving you that stop-start effect, would not be satisfactory.

I also wouldn't be too comfortable advising you to take multiple 30 sec exposures either; my guess is that there could be a build-up of residual heat over the extended time of the multiple exposures, and the problem, as such, wouldn't go away. It would just be deferred, so to speak.

Isn't there provision within the camera for a NR reference photo you can take? And then use that as your reference for the NR algorithms?

I'll check the manual later today and see whether that might offer a solution.

I'm also curious as to whether the D100 shares this issue.

yeh i have read somewhere about being able to subtract a reference photo later, in post processing.

That way i could do my 6 x 10 minute shots, and subtract the noise / heat tinge from the images later.

Has anyone else done this sort of thing? used a "black shot" as a reference for the purpose of simulating NR later on in post processing? ... is there a relatively simple way to do in in photoshop? (CS)

Darb,

No go. That's a dust reference photo - p166 of the manual.

Again, I hope this post is not getting in the way but I would like to advance the nature of the 'exposure' side of this discussion. First off I am still amateur status, so excuse any gaffes. Here is the issue.

In the FE2 I once owned I could double expose the same 35mm film space. In astro or night photography or even normal photography searching for 'trick' effects this could be fun, even if uncertain in its outcome. I don't think this can be done on the D70, but in astrophotography would surely be of value. eg; shift and double exposures on the same film I would guess would provide evidence of new sources of light and hence... new discoveries.

Now I am assuming that with a very stable platform multiple exposures could be superimposed and obtain the same thing or in PP images can be manipulated for the trick side of things. In other words there are many ways to the same end. The question still remains though, can a digital SLR expose the same space twice? Over to you guys..

My first reaction was to answer "no" but then I remembered my little casio zx-3 digital camera, it has a nifty little feature where it lets you take a double exposure. Here's how it works. You take the first shot , lets say a person standing in front of the opera house, you then give the camera to your companion and he or she takes the second photo of you, lining up the background on the lcd. The result is one photo straight out of the camera with both of you in front of the opera house.
Having said all this, I've never actually tried it.

Dargan wrote: The question still remains though, can a digital SLR expose the same space twice? Over to you guys..

No, that's an easy one. Grab a D2x when they become available; it's the first digital with ME capabilities.

phillipb wrote:My first reaction was to answer "no" but then I remembered my little casio zx-3 digital camera, it has a nifty little feature where it lets you take a double exposure. Here's how it works. You take the first shot , lets say a person standing in front of the opera house, you then give the camera to your companion and he or she takes the second photo of you, lining up the background on the lcd. The result is one photo straight out of the camera with both of you in front of the opera house.
Having said all this, I've never actually tried it.

Interesting concept, and interesting way to achieve this.

Gents,

I have attempted to 'mix' a long exposure with a reference 'black' exposure but the result is not as good as using the NR feature of the D70, which is unfortunate.

This is one realm where FILM is better than digital as there is no problem with CCD heating in any silver emulsions. Of course converting from 'analogue' to digital is an issue as there is a loss of definition.

The best way to take photos of 'dark sky' objects is to stack from a VIDEO image. That way you can stack several hundred frames onto one another to get a much better result than from a D70 or any other DSLR. There is plenty of software available that will do this. (I use the Meade Autostar suite)

Let's face it, the D70 wasn't designed with astrophotgraphers in mind, which is why i still use a Nikon film camera when needed.

Astrophotography is an art that takes many years of experience to get it right. I know i still have a long way to go.

My two cents.
Steve.