PDA

View Full Version : An Exercise in Exposure



Gem
02-28-2009, 02:22 PM
Like the title says, this was an exercise in exposure at my brother's wedding (when I was in Dubai) since we were inside and all. This is my other brother. I sharpened it up in GIMP. I'm thinking that it's a bit underexposed? Comments?

f/1.3
exposure: 1/5 sec
iso-100
focal length: 33mm
white balance: manual

tirediron
02-28-2009, 02:32 PM
It's a nice casual portrait, but definitely under-exposed, probably 2/3 - 1 full stop under. It looks to me like the WB may be off a little too ('though you'll need to get the exposure sorted before you can determine that).

Mad Aussie
02-28-2009, 02:39 PM
It's a nice casual portrait, but definitely under-exposed, probably 2/3 - 1 full stop under. It looks to me like the WB may be off a little too ('though you'll need to get the exposure sorted before you can determine that).
What he said

kat
02-28-2009, 03:17 PM
It's a nice casual portrait, but definitely under-exposed, probably 2/3 - 1 full stop under. It looks to me like the WB may be off a little too ('though you'll need to get the exposure sorted before you can determine that).

Okay.. when you say stop here do you mean f-stop, ev stop..? I think this is where I get confused..lol. To many stops :eek:

BlueX
02-28-2009, 03:39 PM
Okay.. when you say stop here do you mean f-stop, ev stop..? I think this is where I get confused..lol. To many stops :eek:

A stop is just a was for photographers to measure and quantify light. When someone says something is 1 stop under, it means the image is under-exposed and needs one more stop of light, either with a wider aperture, longer shutter speed or faster iso (higher number). In your words ev stop.

F-stop generally refers to aperture size. It is confusing. I don't know how many books I had to read before this finally sunk in my head.

tirediron
02-28-2009, 03:40 PM
Okay.. when you say stop here do you mean f-stop, ev stop..? I think this is where I get confused..lol. To many stops :eek:

Yes. A stop is a stop is a stop. Whether it's measuring exposure comp, aperture, or flash. "A stop" is simply a unit used to measure exposure as a whole. When I say that your image was 1 (I'll work in round numbers for simplicity's sake) under-exposed, that means that you needed to double the amount of light that was reaching the sensor.

Your EXIF data shows us that this image was captured with a shutter-speed of 1/5 sec at f3.5 with an ISO of 100. So, to increase the exposure by one full stop would mean either (1) Increasing ISO to 200, decreasing shutter-speed to 1/10 of a second, or increasing your aperture to something around f2.4, or any combination thereof; in other words increasing your ISO to 150 (not that you can, but just to illustrate the point) and decreasing your shutter-speed to 1/7.5 of a second would also give you the same value (approximately).

kat
02-28-2009, 03:49 PM
Yes. A stop is a stop is a stop. Whether it's measuring exposure comp, aperture, or flash. "A stop" is simply a unit used to measure exposure as a whole. When I say that your image was 1 (I'll work in round numbers for simplicity's sake) under-exposed, that means that you needed to double the amount of light that was reaching the sensor.

Your EXIF data shows us that this image was captured with a shutter-speed of 1/5 sec at f3.5 with an ISO of 100. So, to increase the exposure by one full stop would mean either (1) Increasing ISO to 200, decreasing shutter-speed to 1/10 of a second, or increasing your aperture to something around f2.4, or any combination thereof; in other words increasing your ISO to 150 (not that you can, but just to illustrate the point) and decreasing your shutter-speed to 1/7.5 of a second would also give you the same value (approximately).

Okay..now that makes sense. Usually when I get a photo this dark I am one to fool with the shutter speed. So when should you the iso/shutter/or aperture change. Or will they all give you the same result just you have different ways of doing it. LOL..I got the camera out but it's too darn bright in here to try it - but I will tonight!

kat
02-28-2009, 03:53 PM
And the EV compenstion..how does that come into play here.... see I always figured that i got a shot like that..can't change shutter speed for no tripod, can't go any lower (err higher number) with aperture because of lens type that that is when the EV would come in to play..is that right.

Gem
03-01-2009, 01:14 PM
It's a nice casual portrait, but definitely under-exposed, probably 2/3 - 1 full stop under. It looks to me like the WB may be off a little too ('though you'll need to get the exposure sorted before you can determine that).

That's what I was thinking but when we got it printed, it was waaaayyy overexposed :confused:

Marko
03-01-2009, 02:00 PM
I agree this shot looks to be about 1 stop underexposed.

Greg_Nuspel
03-01-2009, 02:11 PM
And the EV compenstion..how does that come into play here.... see I always figured that i got a shot like that..can't change shutter speed for no tripod, can't go any lower (err higher number) with aperture because of lens type that that is when the EV would come in to play..is that right.

EV=exposure value; if you increase the shutter speed or the aperture by one stop you increase the exposure value by one stop. A good explanation is on Wikipedia (http://en.wikipedia.org/wiki/Exposure_value)

Mad Aussie
03-01-2009, 02:27 PM
Gem, is it possible your printing lab may have applied a basic lightening technique (probably just used levels and only the middle range slider) that failed to correctly keep the blacks dark making the image appear milky, which you are mistaking for being overexposed?

JAS_Photo
03-01-2009, 02:52 PM
I am thinking th same thing as MA, the lab may have done a compensation when it was printed up.

Gem
03-01-2009, 02:52 PM
Hmmm, I don't think so because I just tried that and I didn't get the same result. The picture seems to have disappeared so I can't scan it but I fiddled around with the curves and this is almost what the printed picture looked like. I find it too bright, but maybe that's just me?

JAS_Photo
03-01-2009, 03:07 PM
I am no expert, and I hope you do not mind, but here is a quick bit in Lightroom. MA is better at this but even this is an improvement I think.

The top is a bit too red and below a bit too green. You should be able to salvage a photo I think.