Bracketing And Shutter Speed

[decado]

So today, after taking a bunch of pictures with exposure bracketing a bunch of my shots were ruined because with each exposure bracket was a different shutter speed. I'm shooting in M mode because it's the only mode that allows full control over shutter speed, aperture, and ISO, does this shutter speed difference have something to do with that? Do I need to shoot in different modes?

Edit: The shutter speed difference can be pretty substantial, for example on a shot with a 1/640 original shutter speed it will also shoot a 1/2500 and a 1/160.

 

[Overread]

I think you might have a missunderstanding about bracketing mode. The idea of the mode is that the camer takes 3 shots (3 automatic shots for nikon, for canon you have to hit the shutter 3 times) each with a different exopsure. One in the middle (At the settings you have dialed in) and then one shot more exposed and one shot less exposed than that (the amount by which the exposures differ is set by you in the camera - so things like 1 stop, 2 stop, 1/3stop etc). Then you have 3 shots with different exposures which you can either use to select the single best or combine into a tonnemapped image (HDR stuff).

It makes sense that the shutter speed would be the changed setting - keeping aperture (thus depth of field) and ISO the same so that each shot hs the same depth, the same noise and just a varied shutter speed (not a problem for most since this sort of work is done on a tripod)

 

[decado]

But I thought exposure compensation was a completely separate thing, an adjustment of the overall brightness separate from shutter speed, aperture, and ISO. Am I wrong in thinking this? If I shot in a mode that let me use exposure compensation (like AV or TV) instead of only being able to bracket the exposure but not change it otherwise (like M) the shutter/aperture/ISO still stays the same so why doesn't it work the same for bracketing?

The reason this was a problem for me (and I was using a tripod) is that a bunch of my shots were of moving water, or moving creatures, and since I couldn't get the right exposure without exposure compensation I was counting on those bracketed shots to be the same shutter speed with different brightnesses, but since the shutter speed was different from the original settings I ended up with motion blur or not enough motion blur in the bracketed image that would have been right exposure-wise.

Am I completely off base here? And if so, how the heck do photographers with actual talents pull off exposure correctly? So many shots would have been impossible otherwise, like a water fountain with motion blur in which I could not get dark enough even at the smallest aperture and lowest ISO (100), or some turkeys in a fairly dark scene that I couldn't get bright enough with a shutter speed fast enough to stop motion, even at the widest aperture and 400 ISO (800 starts to get pretty noisy). Have I already hit the limit of my $1800 equipment or do I just suck at photography?

 

[KmH]

What camera are you using?

 

[Plato]

The reason this was a problem for me (and I was using a tripod) is that a bunch of my shots were of moving water, or moving creatures, and since I couldn't get the right exposure without exposure compensation I was counting on those bracketed shots to be the same shutter speed with different brightnesses, but since the shutter speed was different from the original settings I ended up with motion blur or not enough motion blur in the bracketed image that would have been right exposure-wise.

With that goal, use bracketing with shutter priority. That will keep your shutter speed constant and three different apertures will be selected to give you the three brightnesses. Also, your brackets are really wide. You're configured for normal, +2 and -2. Try normal, +1 and -1.

 

[Overread]

I think your mistaking how the camera and these auto modes work. Exposure in a camera is controled by 3 things - ISO aperture and shutter speed - nothing else. When you take a shot you set (or the camera sets depending which mode you are in) the settings to the level that you can and then you take the shot.

If you use a semi auto mode like aperture or shutter priority then the camera selects one setting and you the other two. When it does this it will set its setting based on the ambient lighting and attempt to set the setting so that you get a correct exposure in that lighting (Based only on the meter reading). You can use exposure compensation here to tell the camera to over or under expose the shot (by up to 3 stops either way) so that either you can overcone the light tricking the camera meter (for example in very bright conditions its often best to slightly underexpose the shot - say 1/3 a stop or up to 1 full stop underexposure) or for an artistic reason in your shot.

When you bracket again the camera only has those 3 settings to adjust so those are what it does - changes them for each of the bracketed shots as I described above.


The problems you are describing (too much light and not enough light) are part of the pains of photographers - and there will be times when you simply cannot get the shot you want in the lighting you are in - this happens to pros and beginners and its part of the game. For something like your water shots you could come back at a later time - when the lighting is dimmer and softer - or you could use ND filters to block light from entering the lens - and thus letting you use a longer exposure. For the birds you could try boosting local light by flash or - as you say - raising your ISO; that your ISO has a limit as to how far you are prepared to take it is a limitation you will have to learn to work with.

Reading what you write I would recomend getting hold of and reading a copy of Understanding Exposure by Bryan Peterson - I think it would help you a lot and give you some more detail on things

 

[decado]

What camera are you using?

I have a Canon Rebel T1i, I'm guessing my bright light problems could probably be solved by having a camera that does ISO 50? Or some low light problems be solved by a camera that has less noise in the 800-1600 ISO range?

The reason this was a problem for me (and I was using a tripod) is that a bunch of my shots were of moving water, or moving creatures, and since I couldn't get the right exposure without exposure compensation I was counting on those bracketed shots to be the same shutter speed with different brightnesses, but since the shutter speed was different from the original settings I ended up with motion blur or not enough motion blur in the bracketed image that would have been right exposure-wise.

With that goal, use bracketing with shutter priority. That will keep your shutter speed constant and three different apertures will be selected to give you the three brightnesses. Also, your brackets are really wide. You're configured for normal, +2 and -2. Try normal, +1 and -1.

I used various brackets, the only time they were wide like that is when I needed a large bump in exposure whichever direction.

I think your mistaking how the camera and these auto modes work. Exposure in a camera is controled by 3 things - ISO aperture and shutter speed - nothing else. When you take a shot you set (or the camera sets depending which mode you are in) the settings to the level that you can and then you take the shot.

If you use a semi auto mode like aperture or shutter priority then the camera selects one setting and you the other two. When it does this it will set its setting based on the ambient lighting and attempt to set the setting so that you get a correct exposure in that lighting (Based only on the meter reading). You can use exposure compensation here to tell the camera to over or under expose the shot (by up to 3 stops either way) so that either you can overcone the light tricking the camera meter (for example in very bright conditions its often best to slightly underexpose the shot - say 1/3 a stop or up to 1 full stop underexposure) or for an artistic reason in your shot.

When you bracket again the camera only has those 3 settings to adjust so those are what it does - changes them for each of the bracketed shots as I described above.


The problems you are describing (too much light and not enough light) are part of the pains of photographers - and there will be times when you simply cannot get the shot you want in the lighting you are in - this happens to pros and beginners and its part of the game. For something like your water shots you could come back at a later time - when the lighting is dimmer and softer - or you could use ND filters to block light from entering the lens - and thus letting you use a longer exposure. For the birds you could try boosting local light by flash or - as you say - raising your ISO; that your ISO has a limit as to how far you are prepared to take it is a limitation you will have to learn to work with.

Reading what you write I would recomend getting hold of and reading a copy of Understanding Exposure by Bryan Peterson - I think it would help you a lot and give you some more detail on things

I was actually using an ND filter, I'm still waiting on my polarizing filter, I really hope that helps out some. I do understand exposure fairly well now that you've cleared up the compensation part for me, I've just realized how painstaking it can be now. It's just kind of annoying and discouraging, especially since I was shooting in morning light, which is supposed to be some of the best light to shoot in, right?

 

[Stosh]

I used various brackets, the only time they were wide like that is when I needed a large bump in exposure whichever direction.

Based on the above comment, I'm still not sure you understand what bracketing is. Your above statement uses bracketing like I would use exposure compensation. Bracketing is not used to get a large bump in exposure. Bracketing is taking 3 pictures centered around what you think the correct exposure is.

If you need a large bump in exposure, you need to change one of the 3 settings to get it (ISO, shutter speed, or f-ratio). When you're in full manual mode, the light meter still works. I hope I'm not sounding patronizing when I say that, so forgive me if I am. Change any or all of your 3 settings to make the light meter centered or a little high or low depending if you have a tricky scene.

As for your difficult situations you described, nobody here can severely blur a fountain in full sun without a ND filter. ISO 50 would not solve that problem. If you still couldn't get enough blur, use a stronger ND filter.

Freezing motion in a dark area is also difficult. It requires high ISO and/or fast, professional (expensive) lenses.

Isn't this great fun?

 

[decado]

I used various brackets, the only time they were wide like that is when I needed a large bump in exposure whichever direction.

Based on the above comment, I'm still not sure you understand what bracketing is. Your above statement uses bracketing like I would use exposure compensation. Bracketing is not used to get a large bump in exposure. Bracketing is taking 3 pictures centered around what you think the correct exposure is.

If you need a large bump in exposure, you need to change one of the 3 settings to get it (ISO, shutter speed, or f-ratio). When you're in full manual mode, the light meter still works. I hope I'm not sounding patronizing when I say that, so forgive me if I am. Change any or all of your 3 settings to make the light meter centered or a little high or low depending if you have a tricky scene.

As for your difficult situations you described, nobody here can severely blur a fountain in full sun without a ND filter. ISO 50 would not solve that problem. If you still couldn't get enough blur, use a stronger ND filter.

Freezing motion in a dark area is also difficult. It requires high ISO and/or fast, professional (expensive) lenses.

Isn't this great fun?

No, I fully understand what bracketing is. You can bracket (at least on my camera) from 1/3 stop to 2 stops, taking 3 pictures, one at the base exposure, one below base exposure at whatever stop you have it set to and one above base exposure at whatever stop you have it set to. To achieve this change in exposure the camera will automatically change your aperture, ISO, or shutter speed depending on what mode you're in. Bracketing could be used to get a large bump in exposure if you are bracketing at 2 stops, although it would make sense to just change your exposure manually, but I didn't know this when I first made the thread, I thought exposure compensation just changed the overall brightness of the scene, I didn't know it would change things like shutter speed or aperture.

 

[KmH]

.......... I didn't know it would change things like shutter speed or aperture.

OK, now you know it will.