PDA

View Full Version : OVER or UNDER exposure



tim11
02-11-2006, 04:28 AM
Let's say you can only have one shot. No bracketing possible. And for whatever reasons, your metering meter is stuffed up and you are likely to go under or over. So for better result, will you decide to over expose or uner? I mean which one will be better for software enhancing?
Sorry if this sounds dumb to you but I'm curious and the situation might arise someday.

cdifoto
02-11-2006, 04:33 AM
Underexposure because you can always recover in software. You'll just have more noise than you would had you nailed the exposure when you captured the image.

Blowouts from overexposure are unrecoverable.



That said, if you have time to think about intentionally underexposing, you probably have time to expose properly. I've underexposed intentionally to gain shutter speeds that I needed, but it wasn't because I had a choice between overexposing and underexposing. It was because I needed the equivalent of ISO3200 but my camera is only capable of setting ISO up to 1600.

tim11
02-11-2006, 05:00 AM
What about slightly over expose and slightly under; which captures more details? I'm not talking about badly over or under...... but just slightly.

This is in fact an extension from FLASH PHOTOGRAPHY thread. I got the Stofen Omni bounce and doing some homeworks. Most shots at ISO100 are dark (and many lean to under exposure side) and at ISO200 most give brighter pictures (and some lean to over exp.)
There is an event coming up in March which a relative asks me to help taking photos and I'm trying to work out which ISO should I choose to minimise post processing. Just in case you are wondering why I come up with this thread. Thanks again.

timmciglobal
02-11-2006, 05:58 AM
Blown highlights are unrecoverable. I'd always prefer to under then over expose.

Nothing is worse then someones fact with a "white glow" you can't get rid of. Can always change exposure up in software can't move exposure down if there is nothing there to start with.

Tim

TWD
02-11-2006, 09:58 AM
I always overexpose. It's my understanding that there are 2/3's of the pixels on the sensor dedicated to capturing the lighter half of the spectrum and 1/3 to the darker half so you are going to have more room for error on the over exposed range.

In my experiments, I have found that I have been able to recover blown highlights much more attratively than noise from knocked shadows. And more effectively as well because the overexposure doesn't always blow all three channels out so you can work with two or even one channel to recover highlights.

Also, you can add tints to a blown white but you can't edit knocked out black shadows with hue adjustments nearly as effectively, if at all.

And one more reason I overexpose. I'd rather have an image to bright, than too dark because the human eye is more attracted to bright than dark.


Just my workflow description (I shoot RAW, FWIW). Perhaps the experts here will educate me more perfectly. :confused:

JTL
02-11-2006, 10:00 AM
I always under expose, because unfortunately, the metering system in my camera tends to blow highlights (Canon S2). But, even when shooting film (typically Fujifilm NPC), I always underexpose by a third of a stop and get nice "dense", well saturated images that grab people's attention...

JTL
02-11-2006, 10:43 AM
I'd rather have an image to bright, than too dark because the human eye is more attracted to bright than dark.I would challenge that assumption when it comes to photographs. Do the experiment yourself...shoot the same scene over exposed and under exposed...show both to people and ask them to pick one. You might be surprised. Of course, a lot of other variables go into it, such as light source/color/direction, other in-camera settings, overall composition and how the prints are processed or how the monitor/printer is calibrated...

Norm in Fujino
02-12-2006, 12:21 AM
Let's say you can only have one shot. No bracketing possible. And for whatever reasons, your metering meter is stuffed up and you are likely to go under or over. So for better result, will you decide to over expose or uner? I mean which one will be better for software enhancing?
Sorry if this sounds dumb to you but I'm curious and the situation might arise someday.

This is a trick question, since it really depends on the dynamic range of the scene. With film the rule is to expose for the shadows and develop for the highlights, but with digital it's the reverse, much like slide film--expose for the highlights. If you have a scene you know has low dynamic range (everything would be clustered toward the center of the histogram if you could see it), it pays to overexpose (shooting RAW) since you can pull that back down to the middle in development--assuming you dont totally blow the highlights. On the other hand, if you have a scene with high dynamic range, I would expose for whatever I thought was the most important part of the scene, assuming I was going to get it wrong for part of it anyway. Blown highlights cannot be recovered, but most of the dynamic range is clustered at the top of the histogram, so you want to get as close to the top without going over.

tim11
02-14-2006, 01:56 AM
Thanks for feedbacks. I in fact thought over exp. is the answer. And as everything else in photography there is really no direct answer and so many variables involved.