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Underexposed Macro @ ISO800 + FULL SB800

PostPosted: Tue Sep 20, 2005 4:10 pm
by NikonUser
Hi there,

I'm having serious trouble in getting enough light onto my macro subjects...

Today I went out with: D70 + Sigma 180 + Sigma 1.4x + SB800

I set the SB800 at FULL power (manual) and mounted it on the hotshoe. I had the diffuser on. Subjects were close to Minimum Focusing Distance...

ISO 800, F20, 1/125

However even with the flah on full power I still am getting underexposed images.

Can any seasoned macro shooters out there help out a 'newbie' in this area? I'm having to up the exposure by around two stops in ACR or Nikon Capture. At ISO800 this is NOT a good move!!!

Lighting seems to be my main sticking point in macro. The images are usually sharp enough and composed aright.... just VERY underexposed.

Would a ring flash help me at all here? What about getting the flash off the hotshoe and closer to the subject? What am I doing wrong?

Thanks for any input.
Might post some of the macros that turned out 'ok' today a bit later.

Paul

PostPosted: Tue Sep 20, 2005 4:12 pm
by MHD
hmmm... that is strange...

for me, with my 105/2.8 and sb-80DX at full power iso 200 I can stop down to 1/30 ish

PostPosted: Tue Sep 20, 2005 4:24 pm
by NikonUser
Here is an example:

Straight out of the camera. No processing at all:

Image

Same shot with +2.20 ev in photoshop

Image

I know it CAN produce good results... I've done it before. But most of my shots are underexposed. I don't think there is a problem with the flash as it seems to be firing ok and full power is definately very bright! Each step below full power gets less bright

It's obviously something I'm doing wrong. But I'm not sure what.
Is my best bet the flash position?

Paul

Re: Underexposed Macro @ ISO800 + FULL SB800

PostPosted: Tue Sep 20, 2005 4:24 pm
by leek
NikonUser wrote:Would a ring flash help me at all here? What about getting the flash off the hotshoe and closer to the subject? What am I doing wrong?


I've experienced the same with Macro photography and I believe it is because the flash cannot properly reach the subject because of the shadow of the lens...

Getting the flash off the hotshoe and positioning it at the side would probably help. This can be done manually if you are using a tripod for your shots and by using the remote feature of the SB-800... Alternatively, you could use a rig like the one described in this thread...

PostPosted: Tue Sep 20, 2005 4:30 pm
by Hlop
It's, most probably, result of using teleconverter. I've tried my Sigma 105 with Tamron 2x teleconverter and had to use exposure compensation up +5 stops in Aperture priority mode. As TC was removed I didn't need EV compensation

Re: Underexposed Macro @ ISO800 + FULL SB800

PostPosted: Tue Sep 20, 2005 4:34 pm
by NikonUser
leek wrote:
I've experienced the same with Macro photography and I believe it is because the flash cannot properly reach the subject because of the shadow of the lens...



That could be a very good point!!

I've looked at that Wimberly Flash Bracket before but thought I read that you need to have a swiss-arca style setup. From that review you linked to though it doesn't seem the case? Will look into that more!

Thanks for the suggestion and link


It's, most probably, result of using teleconverter. I've tried my Sigma 105 with Tamron 2x teleconverter and had to use exposure compensation up +5 stops in Aperture priority mode. As TC was removed I didn't need EV compensation


I had thought of the TC and it's light loss. +5EV ... that's huge! I thought you were only supposed to loose 1 stop of light with a 1.4x TC!

Paul

PostPosted: Tue Sep 20, 2005 4:37 pm
by Glen
I would think John is right also, with the TC you must have a foot of lens out the front with a working distance of probably 30- 100mm. As Mikhail said, the TC robs .4 of the light.

PostPosted: Tue Sep 20, 2005 4:49 pm
by nodabs
chuck that flash on a cord and just hold it slightly to the side or even over the top (depending on the subject) the other way to check is just take a shot at a low angle to a flat surface in a dark room and see where is lit up and you get your min flash distance

PostPosted: Tue Sep 20, 2005 4:50 pm
by petal666
I was using the sigma 180 with 1.4x tele and 550EX flash and diffuser on the weekend without any trouble. I was using f16 at iso400.

http://www.dslrusers.com/viewtopic.php? ... highlight= (down a few posts)

PostPosted: Tue Sep 20, 2005 4:56 pm
by petal666
nodabs wrote:chuck that flash on a cord and just hold it slightly to the side or even over the top (depending on the subject)
I've tried that before when using extension tubes but a 180macro + tubes + 20D + battery grip + L plate is just too hard to hold still with one hand.

PostPosted: Tue Sep 20, 2005 5:00 pm
by NikonUser
Really nice work!!

Did you have the flash straight on the hotshoe?

Here is one of mine that worked today...

It's a little soft due to noise reduction (ISO800 + Boosting exposure). This shot looked FANTASTIC in the viewfinder (don't they always!!)



Image

Hi

PostPosted: Tue Sep 20, 2005 5:03 pm
by yeocsa
Hi

With the flash so near the subject, your SB800 has more than enough output to wash out the image.

One possibility is due to the use of Sigma TC1.4X - 1.4 stop underexposed. Plus you are on manual mode. The lens and TC may not be reporting the correct information to the flash resulting in underexposure.

Try Aperture Preferred mode. The camera light meter may be able to make the final correction automatically.

regards,

Arthur

PostPosted: Tue Sep 20, 2005 5:15 pm
by Glen
Nice shot Paul. To test some of these theories, why not try it without the TC?

PostPosted: Tue Sep 20, 2005 5:20 pm
by NikonUser
I will certainly do that. I'm stuck inside at the moment but hopefully tomorrow afternoon after work I will be able to get some tests done.

I'm leaning towards the lens obstructing the flash at the moment as being the culprit (will test that too!)

Thanks for all of your great suggestions so far.

Paul

Re: Hi

PostPosted: Tue Sep 20, 2005 5:23 pm
by petal666
yeocsa wrote:One possibility is due to the use of Sigma TC1.4X - 1.4 stop underexposed. Plus you are on manual mode. The lens and TC may not be reporting the correct information to the flash resulting in underexposure.

The flash was on full power in manual mode. There is nothing for the lens and TC to report to the flash.

And yes, my flash was mounted on the hot shoe. Those images have had minimal cropping performed, just to give you an idea of how close I was.

Hi

PostPosted: Tue Sep 20, 2005 5:35 pm
by yeocsa
Image

Canon 10D + 180 Sigma Macro + Ext 25 + Flash (on hotshoe). f22 aperture preferred. 1/30. ISO 400. Tripod mounted.

regards,

Arthur

PostPosted: Tue Sep 20, 2005 5:45 pm
by Alpha_7
Wow, how did you get this bugger to stay still.

Love the colours on this one, amazing looking insect (it must have a funny perspective on life with eyes like that!!). Only downside to this shot I can see is that the wings aren't in focus, but other then that, this is a rippa of a shot.

PostPosted: Tue Sep 20, 2005 8:32 pm
by birddog114
yeosca,
Now you're with the Canon 10D? is this your start from fresh?

HI

PostPosted: Wed Sep 21, 2005 10:48 am
by yeocsa
Hi,

The picture was taken 1.5 years ago in Singapore before migrating to Australia. It was my first digital camera after selling off all Nikon Film Gears. I still have some canon accessories to today. I am using my office's G6 and 2 pieces of 4X closeup filter. So I am back to Canon again.

regards,

Arthur

Re: Underexposed Macro @ ISO800 + FULL SB800

PostPosted: Sun Sep 25, 2005 2:31 am
by KerryPierce
NikonUser wrote:Hi there,

Today I went out with: D70 + Sigma 180 + Sigma 1.4x + SB800

I set the SB800 at FULL power (manual) and mounted it on the hotshoe. I had the diffuser on. Subjects were close to Minimum Focusing Distance...

ISO 800, F20, 1/125

However even with the flah on full power I still am getting underexposed images.

Can any seasoned macro shooters out there help out a 'newbie' in this area? I'm having to up the exposure by around two stops in ACR or Nikon Capture. At ISO800 this is NOT a good move!!!

Paul


Paul, I see no reason for you having this problem, with what you've posted so far. I regularly shoot with the same combo, with the flash mounted on the hotshoe.

The 180 has plenty of working distance for the flash to put light on the subject, even with the 1.4x TC.

For example, this shot was taken well after dark, so the only effective light was from the flash.

Nikon D70s ,Sigma 180mm f/3.5 EX APO Macro IF HSM
1/500s f/25.0 at 250.0mm iso200 using Sigma 1.4x TC with Flash

Image
My guess would be a problem with your metering or you've got some -EV dialed in, or both.

I'd suggest using spot metering and manual modes, with the flash on iTTL. That will work fine for most shots. There will be times that you need to lower the SS or aperture, but I'm not certain why that might be, unless the batteries are getting weak or the flash doesn't have time to cycle.

I've taken a lot of shots like that, at 1/500 f/32 or higher, with the 1.4x TC attached. Those are extremely light limiting settings. The sb800 has plenty of power, in most cases, AFAICT.

PostPosted: Sun Sep 25, 2005 11:56 am
by NikonUser
After playing around with off camera flash in remote mode I've pretty much discovered that it's because of lens shadow.

I don't remember but I may have had the lens hood on that day which wouldn't help!! :oops:

My plan is now to get:

1) Benro KB-2 Ballhead
2) Wimberly Macro Bracket (+ feet for my lenses)
3) Lumiquest Softbox
4) SB-29

I'll see how I go with that lot!!

Paul

PostPosted: Sun Sep 25, 2005 4:02 pm
by KerryPierce
NikonUser wrote:After playing around with off camera flash in remote mode I've pretty much discovered that it's because of lens shadow.

I don't remember but I may have had the lens hood on that day which wouldn't help!! :oops:

Paul


Ah, that is probably the key, Paul. I never use the hood.... Never even thought to mention that. :oops: :shock: Sorry about that.... sheesh. That's exactly why I don't use it, because it substantially shortens the working distance, not only for flash, but the critters don't care if it's just a lens hood and not the lens element in their face. :?

Wish you luck with the other stuff. I have an SC29 and macro bracket for the flashes, but don't use them. Too heavy for me to use hand held. :evil:

PostPosted: Sun Sep 25, 2005 10:19 pm
by petal666
I use the hood on mine and it doesn't effec the flash.