Adjusting exposure in post processing

[tracyh]

I generally shoot large JPEGs rather than RAW, since I've not taken the time to investigate the RAW converters, etc. My question is, though... when I have a shot that's underexposed, I can do some fixing up of that in PS7. I know you can adjust exposure on RAW files... I'm just wondering if there's an advantage with doing this on a RAW file vs. using levels in PS on a JPEG file. Since I struggle with underexposed shots I take with my 550 flash, I'm wondering if it would be to my advantage to shoot RAW... or if I'd get the same basic result as adjusting with levels in PS.
Thanks, Holly

[robertwgross]

You should be able to get close to proper exposure with your 550EX, whether RAW or JPEG file format. If you shoot RAW, you have a little more room to play with in conversion to JPEG or TIF. If you shoot JPEG, you can still fix it up a little, but it depends on how badly exposed it was.

---Bob Gross---

[tracyh]

Yea... perhaps I'm blaming things on the 550 when I shouldn't be. The issue really seems to occur when I'm shooting a portrait with a white background. The subject exposure it's actually pretty decent, but the background is under-exposed... although I feel like I'm lighting it sufficiently (and perhaps it just needs more light). I end up getting kind of an orange cast on the background. That's when I have to screw around with it in PS. I was just wondering whether adjusting exposure levels in post-processing on a RAW file would produce better results than adjusting levels in PS on a JPEG file.

Obviously, I need to work on getting the exposure right out of the camera. This is just an interim solution until I figure out what I'm doing wrong. If you have any ideas on that (getting it right in the first place), I'd love to hear 'em. Thanks!

[robertwgross]

Yea... perhaps I'm blaming things on the 550 when I shouldn't be.

It's always easiest for us to blame the hardware. However, the really smart shooters will learn all of the potential weaknesses of their system and develop work-arounds to minimize the problem.

The issue really seems to occur when I'm shooting a portrait with a white background. The subject exposure it's actually pretty decent, but the background is under-exposed... although I feel like I'm lighting it sufficiently (and perhaps it just needs more light). I end up getting kind of an orange cast on the background.


First of all, for your portrait shot, what camera mode are you using (e.g. Av)? What metering mode? What color balance setting?

Orange cast tends to be "tungsten glow" which comes from ordinary incandescent light bulbs. So, if you have a mixture of good flash light from your 550EX, and bad orange light from ambient lighting, then what should you do to cut out the bad part? Think about that for a second, or else think about it the other way around. Theoretically, if you wanted to increase the effect of ambient orange lighting, what would you do?

---Bob Gross---

[tracyh]

Sorry. Forgot to mention that I'm using Program mode. My next step was to play around with Av or Manual mode to see if the metering would expose more for the background, allowing the flash to light accordingly.

Concerning the background lighting--- I'm using regular incandescent bulbs in some clip-on work lights, but they're the "daylight" bulbs. Have you heard of those? I was hoping that would help the situation. I believe they're 100-150 watts each (I'm not near them to check it). I must admit that I'm a little fuzzy on the different light types (tungsten vs. incandescent, etc.). Do you have some suggestions on something I could use for contiuous lighting on the background?

Thanks again for all your help...

[yb98]

I generally shoot large JPEGs rather than RAW, since I've not taken the time to investigate the RAW converters, etc. My question is, though... when I have a shot that's underexposed, I can do some fixing up of that in PS7. I know you can adjust exposure on RAW files... I'm just wondering if there's an advantage with doing this on a RAW file vs. using levels in PS on a JPEG file. Since I struggle with underexposed shots I take with my 550 flash, I'm wondering if it would be to my advantage to shoot RAW... or if I'd get the same basic result as adjusting with levels in PS.
Thanks, Holly

Shoot in raw. If you are not convinced look here:
http://photography-on-the.net/forum/showthread.php?t=24713&highlight=

[Scottes]

I have to agree with the others.

1) Find workarounds for crazy equipment.
2) Shoot in RAW
3) If necessary, fall back to Photoshop: http://photography-on-the.net/forum/showthread.php?t=35041

[scottbergerphoto]

FYI, It's better to slightly overexpose in raw then to underexpose. Side by side comparisons of images shot slightly under vs. slightly over exposed show the recovered overexposed ones come out better. That is because so much more data is captured in the right side of the histogram(Expose to the Right at www.luminous-landscape.com ).

Secondly, an easy way to to get a bright white backgroud is to buy a small battery operated digital slave flash.
http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=search&Q=
I use (2) Morris Mini Slaves and (2) Mini Slave Wides. You can drop the Wides in corners of a dark room so that it lights up the whole room. The Mini's are directional. You can put it on the floor and point it at the background.
Put the 550EX on Manual and use the distance scale to adjust the f stop. Use FEC to adjust the 550EX based on the histogram.
Scott

[chtgrubbs]

Holly:

To control the exposure of your background you need to switch to manual mode. When working with a combination of continuous light and flash, the exposure for flash is controlled with the aperture, and continuous source is controlled by varying the shutter speed. To make the background lighter in relation to the flash exposure use a shutter speed one or two steps slower than the camera would select in the program mode. Review a couple or three test shots until you nail the right combination of speed and aperture.

Charles