Some more experience with SB800 flash

[Spooky]

I posted a while back on my first impressions with my SB800 when I used it for a model shoot indoors at night and got some reasonable results.

I used it on the beach on Saturday for a model shoot. The day was very bright and I needed some balance fill flash for when the model wasn't facing the morning sun.

I selected TTL BL mode.

I was using my 70-200 VR lens and wanting some shots with the background blurred out (as I find this lens does beautifully). I was therefore shooting at f2.8 part of the time and in Aperture priority mode which is what I normally shoot in.

Unfortunately I was getting the error message "Hi" quite often and many of the shots the background was badly overexposed.

At the time I wasn't sure what was going on and by doing a bit of research on the net I believe I now understand what was happening though I am hoping someone could suggest solutions.

It appears the D70 when in A mode with TTL BL has a maximum shutter speed of 1/500. Why this is I don't know.

I am guessing that this limitation meant too much light was getting in at f2.8 and therefore overexposed the images.

Now, how does one get around this?

I realise closing the aperture down sufficiently would fix the problem once enough light was blocked however I was shooting f2.8 for a reason.

If you go to M mode to control the aperture and shutter then TTL BL does not work. The SB800 reverts to TTL mode.

Any ideas?

[xerubus]

couple of things you could do in this case.

- turn exposure down on the sb800 so that you can keep your 2.8
- go remote with the sb800
- bounce the flash off of a reflector to the side of the model etc etc

personally i'd shoot M manual with sb800 remote.

cheers

[JordanP]

I posted a while back on my first impressions with my SB800 when I used it for a model shoot indoors at night and got some reasonable results.

I used it on the beach on Saturday for a model shoot. The day was very bright and I needed some balance fill flash for when the model wasn't facing the morning sun.

I selected TTL BL mode.

I was using my 70-200 VR lens and wanting some shots with the background blurred out (as I find this lens does beautifully). I was therefore shooting at f2.8 part of the time and in Aperture priority mode which is what I normally shoot in.

Unfortunately I was getting the error message "Hi" quite often and many of the shots the background was badly overexposed.

At the time I wasn't sure what was going on and by doing a bit of research on the net I believe I now understand what was happening though I am hoping someone could suggest solutions.

It appears the D70 when in A mode with TTL BL has a maximum shutter speed of 1/500. Why this is I don't know.

I am guessing that this limitation meant too much light was getting in at f2.8 and therefore overexposed the images.

Now, how does one get around this?

I realise closing the aperture down sufficiently would fix the problem once enough light was blocked however I was shooting f2.8 for a reason.

If you go to M mode to control the aperture and shutter then TTL BL does not work. The SB800 reverts to TTL mode.

Any ideas?

I'm no flash guru as others on the forum but I can pass on why the shutter speed is capped at 1/500th when using the flash. Basically it is the cameras max sync speed. I believe you can trick it (I've seen others post where they have used tape over certian contacts to get around it)

I'd also suggest another way around things is to go higher with your aperture. If you are fully zoomed (at 200mm) with the 70-200vr you should have a shallow depth of field even at f5.6 - f8.

Alternatively do something about your lighting by choosing different times or venues - traditionally model lighting is much better as soft lighting. I always head for shade when shooting in strong light through the day.

Others will no doubt have great suggestions,

[JordanP]

would love to see some results btw

Cheers,

[gstark]

Taping over the two rearmost contacts (IIRC) will disable the 1/500 synch speed limitation, thus permitting you to shoot at any shutter speed you wish.

But yes, that will also lose you the iTTL facility, but IMHO that's not a great loss considering what you were wanting to do.

I would have switched to full manual, aperture to 2.8 as you wished, shutter speed as metered -2/3 stop, then set the flash to A and f2.8 (play here - f3.5 or f4 may have been ok too) and see how you were goining using the LCD and histogram.

[Spooky]

Thanks for your suggestions guys.

I have posted a few pics in the image review forum from the beach shoot..

Craig

Also just did a post in the image review forum with some pics from my first wedding that I did the other day.

Cheers

[JordanP]

excellent - just hopping over for a look now.

Cheers,

[Matt. K]

Your problem is that at ISO200 the exposure will be 1/500th at f/11 or f/8. on a sunny day. In order to use a bigger f/stop you would need a nuetral density filter. This would allow you to use a bigger f/stop and fill flash.

[Hlop]

Taping over the two rearmost contacts (IIRC) will disable the 1/500 synch speed limitation, thus permitting you to shoot at any shutter speed you wish.

Do you mean to put some tape on contact to cover them or shortcut contacts?

[gstark]

Taping over the two rearmost contacts (IIRC) will disable the 1/500 synch speed limitation, thus permitting you to shoot at any shutter speed you wish.

Do you mean to put some tape on contact to cover them

Yes.

[Hlop]

Thanks Gary. Is anything else affected by this or sync speed only?

[gstark]

Mikhail,

Obviously there's going to be some significant effect on camera-flash communications, and I have no idea of the extent of this.

But if you're shooting with the camera on M and the gun on A, it's all moot anyway.

[Onyx]

Mikhail, when I discovered thsi taped contact trick, I did experiment a little. It retains full iTTL functionality AFAIK, the only thing is, the camera now defaults to slow sync mode (ie. no 1/60s shutter limitation as by default).

Spooky, you've discovered a user induced limitation of using Aperture Priority - that is, the user needs to know exactly what's going on wrt to exposure for the given lighting and shooting conditions. Now you know why Ken Rockwell raves on like a lunatic about flash sync speeds - it is one of few features on a camera that has a real effect on images. Imagine if you were shooting a D100 or earlier camera with of 1/180s shutter - all your photos would have been one further stop overexposed.

[kipper]

You sure it retains full i-TTL Onyx? I just taped over the rear two contacts then and even though it says TTL it's fully manual from what I can tell. In TTL every comes out overexposed. So I switched to GN or Manual and keyed in all the info (eg. subject distance, iso, aperture). Then it exposed correctly. I had the issue of trying to shoot into some reeds on a really sunny day (in Melbourne) on Monday. However it was 1/500th and aperture 5.6 and it was about 1.5 to 2.0 stops over exposed. It was then I realised I couldn't crank the shutter speed past 1/500th, so I switched the flash off. Looked into high speed shutter sync in the manual today, disappointed that the D70 doesn't offer it but I guess taping the contacts is an alternative. Or as Matt K sugested get an ND filter. However a 77mm ND (do they make plain NDs for the 77MM thread I know you have to use Cokin for grad) might cost me a fairbit, haven't even got a UV filter