Whatcha Think? Exposure Difficulty

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B_Kosanda

Outstanding In My Field
#1
I have a question on the obvious exposure difficulties shown in the second photo. The first photo is my set-up shot to make sure the camera is working correctly. The second shot is taken 5 seconds later and is under-exposed.

Both are taken in shutter priority, at 1/250. The first got exposed at f6.3, the second got exposed at f10. Both are taken with a Canon XSi in Evaluative Metering mode.

My thought is that the locomotive headlights may have over-biased the exposure setting. I expected the evaluative metering mode to be less susceptable to point sources of light. Is another metering mode a better choice?

Bill
 

kenw

5th Generation Texian
#2
I usually use a center-weighted or even spot for most shots anymore. As long as the spot is not too close to those headlights. Eval or overall with much sky will almost always underexpose the subject.
 

B_Kosanda

Outstanding In My Field
#3
Does it really matter if your using the Manual Mode on your Camera. I tend to use the Manual Mode 99.9% of the time now.
I have not been using manual mode, just shutter priority (TV), just to keep from blurring the shots. But I'm getting pretty good at knowing what the camera should be selecting for aperture, so I guess I could go to Manual mode and just forget the metering mode.
 

B_Kosanda

Outstanding In My Field
#4
In that second shot above, I knew that f10 was too small of an aperture when I was taking the shots, but of course the train was approaching at 40 mph and it was too late to make a change...
 

Pat

Photo Critiques Welcome
#5
I like to use matrix metering to evaluate the scene. If the head lights are going to be pointing toward the lens I'll switch over to manual.
 
#6
Yes headlights are a huge source of meter fooling especially on telephoto shots. Another work around is to push down on the AE lock before the train gets too close. Otherwise shoot manual.
Pete
 

kenw

5th Generation Texian
#7
Does it really matter if your using the Manual Mode on your Camera. I tend to use the Manual Mode 99.9% of the time now.
Metering is a reading that the camera takes to judge the exposure that you or the camera have selected. Canon has 3-4 different metering modes: Evaluative, Partial, Spot and CWA (some older don’t have Spot). Even in manual shooting (“M”), the meter is still judging the scene and using this to give you the blinking overexposure indicator (as an example). It uses the AF point you have selected as the starting point for the metering (altho these can be de-linked)

Evaluative is where it takes many readings of many points, Partial uses only the central portion and ignores the rest, Spot is like Partial but uses a smaller central area and CWA is Center Weighted Average which uses the entire field but emphasizes the center a bit more.
 

B_Kosanda

Outstanding In My Field
#8
Allan's suggestion got me thinking about using Manual mode, especially given that my camera will still provide exposure indications in the viewfinder. I think this will essentially allow me to set up the shot in advance and force the camera to stay at that setting for the shots I take when the train shows up.

Bill
 

kenw

5th Generation Texian
#9
Bill, if you use one of the priority modes, you'll do virtually the same thing. It's why I use shutter priority: I can guarantee the shutter speed ahead of time, and at the focal lengths of trains aperture is largely moot. A few test shots will give me a histogram to review if I have time.

According to my DoFMaster calculator, using a 50mm lens at 100 ft gives infinite DoF all the way down to f4.5.
 

B_Kosanda

Outstanding In My Field
#10
Bill, if you use one of the priority modes, you'll do virtually the same thing. It's why I use shutter priority: I can guarantee the shutter speed ahead of time, and at the focal lengths of trains aperture is largely moot. A few test shots will give me a histogram to review if I have time.

According to my DoFMaster calculator, using a 50mm lens at 100 ft gives infinite DoF all the way down to f4.5.
Ken,
I have been shooting shutter priority, because I care most about the shutter speed. But, my problem as you can see in my two photos posted is that the light meter is getting confused by the locomotive headlights. At least that is what I think is happening.

Bill
 
#11
I have experienced similar change-in-exposure sequences like this, too. I am using a Rebel XTi.

Like Allan, I find myself shooting more and more in manual mode. Starting off in shutter-priority at 1/500 if I can (at ISO 400) in any kind of good lighting, I will metering off the ballast, and switch over to manual mode and match the exposure.

I will then take a test shot of the "scene" and see how things look. The histogram is helpful, unless I'm in the forest, where the dark trees will throw things off.

I don't use exposure lock for one reason - I've had it unlock before for some reason or another (like the camera powering-down?). Also, I like to use TV mode to set my initial exposure just in case lighting changes (a loner cloud, for example) as the train approached or I just "chicken out" with manual mode. I can throw it back to TV mode and hope for the best.

Funny, I hardly ever had such exposure challenges when I was shooting my EOS-10s 35mm usually in Shutter-priority with Kodachrome 64!
 

kenw

5th Generation Texian
#12
Ken, 16 16
I have been shooting shutter priority, because I care most about the shutter speed. But, my problem as you can see in my two photos posted is that the light meter is getting confused by the locomotive headlights. At least that is what I think is happening.

Bill
Ok, then a solution might be to select a different focus spot which will also change the metering spot. Using the ballast as Rob mentions is always a good choice and is typically my solution.

Of course manual will work too, I just think it is overkill and has a lot of other issues.
 

drew mitchem

I'm here.......sometimes!
#13
:eek: Looks like someone was at Elsberry on the K-Line..... :D
I always shoot in manual mode now, so I have complete control over how the shot will turn out. After shooting with the Fast man and Shutter Priority and getting varied results, I learned how to use Manual settings. Everything has been just fine ever since. I do still use Auto Focus though, as I do not trust my ability to manually focus the lense.
 

B_Kosanda

Outstanding In My Field
#14
:eek: Looks like someone was at Elsberry on the K-Line..... :D
I always shoot in manual mode now, so I have complete control over how the shot will turn out. After shooting with the Fast man and Shutter Priority and getting varied results, I learned how to use Manual settings. Everything has been just fine ever since. I do still use Auto Focus though, as I do not trust my ability to manually focus the lense.
I believe I am now a Manual Mode convert. I've been out a few times and shot only in manual mode. It is easy to use, especially with the metering indications shown at the bottom of the viewfinder on my camera.

Thanks everyone for chiming in.

Bill
 

dw_trainPhotoguy

commercial photographer
#15
I have found that getting a shot with a good histogram that's biased to the right but not blowing out the highlights using manual mode gives me the best results. I don't get the underexposures that Auto gives me when the headlights throw the meter off. Also if you can, shoot raw files and process them later. You get more detail in the file to work with later. Jpegs are the worst because the file thows out lots of detail when the camera creates them.
 

BarrySr

Roster sniper
#16
Ken is spot-on. The XSi was my first DSLR (NOT my first SLR), and his info is correct. If your mind is quick, of course manual will do, but I use spot metering on the 7D and haven't got a mis-read in a looooong time.

Just stay away from 'dem headlights.....:cool:
 

kenw

5th Generation Texian
#17
Barry's digging up some old threads with his catching up, and i mean that in a very good way. Since we first started this thread I have modified my normal procedure in a way that I find helps a lot in this area. If you camera will allow, enable the 'back-button AF & meter" option. What this does is separate the shutter button and the meter and/or AF action. (Canon allows you to back button the AF only, the Meter only or both) I have mine set that I can press the back button to focus and set the meter, then reframe the shot for composition, then when I press the shutter the metering and AF do not change. Typically my sequence is: back-button focus and AF on the ballast at the point the train WILL BE. The ballast is neutral and I can tell pretty quickly what the resulting Av will be (shooting in Tv). If all is fine, then when the train gets to that spot, press the shutter and the headlights won't affect the settings in the least because the shutter is all I'm doing, as the AF and meter were separated from the shutter button and set without the lights being there.

If you are in a highly mobile situation, keeping your thumb on that rear button will keep the focus and meter moving as it needs to as things change, similar to having it all on the shutter button again.
 
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#18
I've been reading photo forums and manuals for years, and I have to say, that's the best explanation of using the * button, on the back, that I've ever read. So many just say "I use the setting for focus on the *" :confused:

I see now this is an older thread. The reason why people got "better" shots with film, is it has a much wider latitude than digital.

Yes, the headlights will confuse the sensors and the metering. End of story. But for the preset (Manual Reading), I usually use a Sunny spot of grass or trees, that's going to be in the middle. Ballast is a good example but can vary.

With film you could expose for the shadows and that was the easy standard. Now I expose for the shadows and have the camera set +1/3rd, which has worked out best personally. It's better to make things darker, than to bring up shadows and get that speckled noise.

Some people will argue that you can have whites blown out. Yes, but you won't have shadow areas that look like confetti. LOL

There's no perfect answer, but I prefer shooting to the right a tiny bit and adjusting back for nice contrast.

Lets see if I got this right. I spend all this money on lenses and a camera that has the newest processors, all kinds of automatic settings, custom functions and features... then I shoot Manual?

Yes, very often, depending on the situation, that's right. :cool:


Barry's digging up some old threads with his catching up, and i mean that in a very good way. Since we first started this thread I have modified my normal procedure in a way that I find helps a lot in this area. If you camera will allow, enable the 'back-button AF & meter" option. What this does is separate the shutter button and the meter and/or AF action. (Canon allows you to back button the AF only, the Meter only or both) I have mine set that I can press the back button to focus and set the meter, then reframe the shot for composition, then when I press the shutter the metering and AF do not change. Typically my sequence is: back-button focus and AF on the ballast at the point the train WILL BE. The ballast is neutral and I can tell pretty quickly what the resulting Av will be (shooting in Tv). If all is fine, then when the train gets to that spot, press the shutter and the headlights won't affect the settings in the least because the shutter is all I'm doing, as the AF and meter were separated from the shutter button and set without the lights being there.

If you are in a highly mobile situation, keeping your thumb on that rear button will keep the focus and meter moving as it needs to as things change, similar to having it all on the shutter button again.
 

Rod Williams

Retired throttle jockey
#19
I have a question on the obvious exposure difficulties shown in the second photo. The first photo is my set-up shot to make sure the camera is working correctly. The second shot is taken 5 seconds later and is under-exposed.

Both are taken in shutter priority, at 1/250. The first got exposed at f6.3, the second got exposed at f10. Both are taken with a Canon XSi in Evaluative Metering mode.

My thought is that the locomotive headlights may have over-biased the exposure setting. I expected the evaluative metering mode to be less susceptable to point sources of light. Is another metering mode a better choice?

Bill
I'm simply wondering if you have a problem with the camera. Two stops variation with not a lot of change in the scene seems odd. I doubt that a headlight would do that much at that angle.
 



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