7D - Wild Exposure problems

Discussion in 'Canon EOS' started by hjoseph7, Oct 30, 2010.

  1. My 7D is starting to show wild and temperamental Exposure problems. For instance I tried to take a picture outside of a flower bed this morning in 'P' mode and the image was completely blown out ! I figured it was operator error so I took the camera inside and took some more test pictures. Everything seemed to work well until I began using the pop-up flash. That's when I started noticing that the exposure changed with each picture I took. One picture was under exposed while the next picture was over exposed and the next picture was properly exposed. This was without changing any of the settings !
     
  2. It seems as if you selected exposure bracketing.
     
  3. But then he'd probably notice 3 pictures being taken (unless drinking in a loud club). Exposure is very consistent on my 7D and doesn't change unless I change it or the conditions change. So maybe his 7D is hosed (or needs a PRAM reset) as that is not typically behavior. With that said, 7D auto ISO is pretty weird and seems to set abnormally high settings (e.g., ISO 3200 when 400 or 800 will do fine), so I ride the ISO with my finger.
     
  4. Harry - Is the Quick Control dial (dial on the back) locked? If it is not, then it acts to alter your exposure in the P, Av & Tv modes (maybe others. I'm new to the 7D too...), but not in "M". You'll see the exposure compensation scale in the LCD and in the viewfinder: -3..-2..-1..0..+1..+2..+3. There will be a "cursor" below one of the positions in the scale. You want to rotate the quick control dial until that cursor is below the "0", and then lock the quick control dial with the switch next to it.
    Check your manual, esp. page 37.
     
  5. I just got my 7d, but I noticed something at an airshow yesterday that sounds similar to your problem. Since angles and subjects were changing frequently, I did most of my shooting in P mode, but I set the ISO at 100 since we were in bright sunlight. Out of 400 exposures, I had two in a row where the exposure was off noticeably. In my case, they were both well underexposed. They really stood out when scrolling through DPP since both the subject and the sky were much darker than in any of the other pics. I was shooting raw, so this was definitely a metering or exposure problem. I also had the control dial locked all day to prevent accidentally changing the exposure. I also saw a post the other day where someone was complaining about the 7d metering certain scenes incorrectly.
     
  6. I suspect (like Mark, Puppy and Lobo) it is something you have set rather than a failure. I find my 7D has always been very good at metering but like any camera has issues in difficult lighting. I must admit that I never use P mode (even since the old A1 introduced it I have have just stuck with Manual, Av or Tv) and I do not use auto ISO. I suggest that you first use the camera in Av or Tv mode and set the ISO manually (pressing the Q button and check the mode, ISO, aperture, exposure compensation, shutter speed and metering mode). Then take some shots in fairly straightforward light (not backlit etc...) and test the metering. I would check, evaluative, spot and partial (you can check centre weighted but this is a mode I find I never use as evaluative does a better job). I just played with my Auto ISO and found that it works fine but tends to set higher ISOs that I would choose.
    On Mark's comment on the prior post on 7D metering this appeared to be a clear case of user errors - the claim on that post was that the users previous Rebel never needed any exposure compensation. All cameras need exposure compensation under certain lighting conditions - the 7D algorithms however are slightly different from almost all prior Canon bodies as it tends to need less compensation. I think this is due to the fact that the metering takes into account subject colour. You should try and make a habit of using the quick preview and rear LCD of the camera before you start shooting as I find that scope of settings on a DSLR is such that you can have something you do not want selected. Unlike Larry I have never found an issue with keeping the rear control dial switched on (indeed on the EOS 1NRS you were unable to turn it off as Canon used the Off position as the R - high speed mode). What I do find a problem is the mode selection button can get rotated easily . In my case this is usually obvious as it tends to get turned onto the CA or Green rectangle modes where the rear LCD display very different information.
    To use exposure compensation and AEB the simplest method is to select the exposure compensation range on the rear LCD so it is hilighted in blue. Then the rear control wheel will adjust the exposure and the main dial by the shutter will give you bracketing. If you rotate the main dial clockwise you will see two more little marks under the exposure compensation dial as you continue to rotate the spread of these marks increases. The camera will take one shot at each setting indicated by the mark (e.g. -1, 0 and +1). In the custom functions you can chose the order in which these three shots are taken and the expose increments (1/3 or 1/2 of a stop). If you rotate the rear control dial you will see the group of three exposure will move to give an exposure compensation. I strongly recommend that you get familiar with exposure compensation and AEB if you want to shoot landscapes as it is one of the great features of digital. In difficult light you can bracket you exposure (and there is no real cost to doing so) and you can always use photomerge to combine multiple shots (this is better if you use a tripod).
    Interestingly when you switch off the camera AEB will be cancelled but any exposure compensation will not be (hence it is a good habit to check the rear LCD - although the compensation is displayed in the viewfinder and on the top LCD). If you use AEB in single shot motor drive mode you need to press the shutter once for each setting. In the continuous modes it will just keep cycling through the AEB settings - I find low speed continuous best any you just count three exposures. As Lupo says AEB is cancelled by use of the flash.
     
  7. I'm back tracking to see what I might have selected to cause this, but so far the only thing I can tell is an under exposed picutre taken with these settings 1/60 @ f5.6 and the same picture came out over exposed at 1/60 at f5.6 ? I had an important shoot today so I defaulted to my 30D because of that unfortunately. In any case I'm under warranty.
     
  8. I haven't changed anything in the the settings or the custom functions (I just got this camera a few days ago). And I'm not a new user; I've been an amateur photographer for 25 years starting with a well used Canon A-1 back in the day.
    My problem sounds similar to the OP's and it actually may not be an exposure problem. The EXIF data shows that all three of my photos had the same exposure settings (and they were all very similar photos). The problems I had were on two (actually three) photos in succession. It was a plane passing by showing the underside (painted dark) against a clear, blue sky. Subject size was roughly the same in all three photos. Photo one was exposed correctly, photo two has the appearance that it is underexposed by about 2/3 stop and photo three by over a full stop. The next photo (not taken in rapid succession) was exposed correctly. Now it is possible that the light changed enough to warrant an exposure change and the camera failed to make it, but I seriously doubt it. It was bright sun and my shooting angle didn't change by more than 20 or 30 degrees right to left (and not at all up or down).
     
  9. Harry,
    Shooting conditions you describe (1/60 of sec, pop-up flash) remind me of something. Can I can assume you're shooting indoors and the ambient light is fluorescent lamps? It could explain wild underexposures due to invisible blinking of the lamps with frequency of 60Hz or 50Hz depending on where you live.
    Does it sound reasonable?
     
  10. Mark - is it possible you were using a partial or spot metering. In this case the metering would respond to the colour of the object in the area being metered and hence may vary significantly.
     
  11. Hi. For general photography my 7D exposure is spot on, but there rare odd occasions when it seems way off or inconsistent between shots. I have noticed that in evaluative mode the exposure system seems to take greater notice of what's under the focus point than other Canon cameras I've had. So, if I'm photographing a dark object it will surely make that 18% grey despite what ever the surrounds are, and similarly for light objects. Once I noticed this it hasn't been much of a problem as I can take a test shot and check when I think the subject may cause problems. I generally resort to exposure compensation or M ( which I find easier as EC needs a bit of awkward manipulation (half press shutter, at the same time twiddle wheel at the same time look for the result in the little window).
    I photograph steam locomotives and these really are hard work to expose just right if you just leave the camera to do its thing. Trouble here is its hard to predict what the camera will do, so it is safer to expose these kinds of subjects manually.
     
  12. Philip - No, I've never taken this camera out of evaluative metering. The only change I made was to set the ISO at 100. I'm pretty sure this is not a metering or an exposure problem. There's something else going on here. EXIF data for all three photos shows the same exposure settings (in my case, shutter speed 1/640 sec, f/8, ISO 100) and I believe that all three photos did indeed warrant the same exposure settings. I believe the OP said the same thing, that his exposure settings didn't change, but the images looked drastically different. The fact that my images were so similar in composure, had the same exposure settings but completely different appearances indicates something's not right and it sounds very similar to the OP's problem. Over the next few days, I'll try to test is under similar circumstances (though obviously I can't recreate the airshow). I took over 400 pictures that day and only two were affected, but I'd rather not have any.
     
  13. I will download the pictures I took later on today. No, I was not shooting at Auto ISO, the ISO was set at 100. AEB auto exposure bracketing was disabled. Exposure compensation was set at Zero. Not sure if the Quick control dial was locked or not. The pop-up flash was engaged and I fired off about 10 shots in Manual mode. The first 2 shots were under exposed then the next 2 shots were over exposed without my changing any of the settings as far as I know. I was shooting under Tungsten and ambient light. Earlier during the day, when I tried to take a picture of a flower bed, the pictures came out way overexposed by 3+ stops in "P" mode. Not sure if selecting one focusing point(the center focusing point) had anything to do with it ?
     
  14. Harry, it sounds like you and I have the same problem. Using "P" mode and manually setting ISO, you are getting images that appear to have different exposures despite data showing that the same exposure settings were used. In your case, using flash with an identical subject, multiple pictures most certainly called for the same exposure settings and the ones that you indicated earlier look reasonable. Moreover, if the exposure was off, then the images should have recorded the same error (either all underexposed or all overexposed and to the same degree). That's why I'm no longer convinced that this is an exposure problem. It sounds like the sensor is not correctly recording the image. I'll be curious to see your pictures and I'll try to download mine as well.
     
  15. Sorry, I re-read your last post and you weren't using "P" mode for all of your pictures, but you were getting different results with the same exposure settings. I'll try to duplicate your situation using flash and a combination of "P" mode and Manual settings.
     
  16. Philip said:
    Unlike Larry I have never found an issue with keeping the rear control dial switched on​
    I wasn't trying to say that it's an "issue", but rather that it is not that hard to inadvertently bump the dial while handling the camera. Before I got my 7D, I borrowed a 30D, and learned the hard way about making sure the dial was locked! Whether I was accidentally bumping it, or absent-mindedly twiddling it, I'm not sure, but once I set exposure comp to 0, and locked the dial, the photos came out much more consistent.
    Of course, since I now own a 7D, I'm much more aware of the dial, the displays, and the effects of moving the dial in certain modes.
    At the least, checking that Exposure comp is at 0, and the dial is locked while in P, Tv or Av modes, eliminates one potential source of exposure changes, and helps narrow the possible culprits.
     
  17. Thanks Mark trying to explain this baffling problem is not easy. The thing is, that other than the 2 situations which I mentioned, one with the pop-up flash(manual) and the other with the flower bed(P) the camera works perfectly. I did notice another issue last night, but haven't had the time to investigate yet. Some pictures I took have the label 'CF: ' displayed on the top right hand corner of the playback screen, (which I think means Custom Function) even though as far as I know, none of the Custom Function settings are enabled ?
    Mark thanks allot, at least I know I'm not dreaming, or had one too many. I will try to write down these problems tonight for when I have to deal with Canon Customer service. If it is a problem with the camera, then I want a brand new one.
     
  18. No problem, Harry. Like you, I'd like to figure out if this is a problem I need to address soon. I've had my camera for less than a week and this problem showed up the first time I subjected it to extensive use.
    Just out of curiosity, have you applied the firmware update that was made available in July? My camera came with version 1.2.1 and I didn't upgrade to 1.2.2 until yesterday, so I was shooting with the old firmware. Don't know if it may help, but glitches like this sometimes resolve with a firmware update.
     
  19. It sounds like you may both have an issue. It is also possible that I have the same issue but have not noticed it. The 7D is not my main body and I usually just use it for sports (mainly ice hockey and ski racing) where it is slowly taking over from my 1DIIN. I have probably taken about 20,000 shots with the 7D but have not really noticed the exposure issue you describe. It is possible that given lighting issues it was not that apparent in sports shots although 2-3 EV would be very obvious.
     
  20. "My camera came with version 1.2.1 and I didn't upgrade to 1.2.2 until yesterday, so I was shooting with the old firmware"
    Mark I haven't even downloaded the new version of DPP, or even hooked up the camera strap. I mostly been shooting out of the window, or in my living room. Yesterday is the first time I took the camera out. I did notice that my camera came with version 1.2.1 firmware and the newest version is 1.2.2, however, if I remember correctly version 1.2.2 does not address the issues we are encountering. In any case I will down load the new version to see if it helps, but I doubt it. A couiple of weeks ago I read a post that someone was having problems with the 7D's exposure. Something about the camera's AE being fooled under certain situations, maybe I can find it in the archives.
     
  21. I don't think the firmware will make a difference either, but I have seen it happen. Sometimes, while fixing other issues, a faulty bit of code gets replaced with the proper one. I won't hold my breath, but it is possible.
     
  22. I spoke to a friendly Canon Rep today about my problem and he said it might be the lens not the camera. He asked me to send him all the problem pictures I took via email so he could analyze them. Here is a picture of the flower bed i tried taking earlier in mode 'P'. Next I will post a picture of a properly exposed flower bed in manual mode. The exposure shot in taken in 'P' mode was way off, this is what is worrying me. Sorry but i don't have photoshop on my new computer yest so i could not combine two pictures into one using DPP.
    00XbEa-296843684.JPG
     
  23. Picture #2 with -1 exposure compensation
    00XbEc-296845584.JPG
     
  24. Here is the same picture taken using Manual mode and relatively properly exposed. Now that I think about it it could be that since I was using the 24mm TS lens and the lens was set to 'Tilt' this could have affected the exposure settings.
    00XbEj-296847784.JPG
     
  25. I solved one of the problems with my 7D. Apparently when you use a TS lens and the lens is in the shift, swing or tilt positions and the camera is set to 'P' mode, wiild variations in exposure are possible mostly over exposures. I took a couple of shots in 'P' mode with the lens tilted and they all came out over exposed ! So that means Manual exposure is the best/only way to go when using the lens the lens in this fashion.
    I still haven't figured out why some pictures come out dark and others light when using the pop-up flash, but it could be that the flash is putting out more or less power for one reason or another. I'm trying to work this out with the Canon Rep and will keep you posted.
    With that I apologize to Canon and all the 7D fanatics on this forum.
     
  26. It looks like the problem with some pictures coming out darker than others with the same aperture/shutter combination settings might be attributed to slight variations in shooting angle, and the way the flash reflects of the white wall but I 'm still investigating.
     
  27. I still have not ruled outproblem #2. The next 2 pictures were taken with the same exact settings.
     
  28. I still have not ruled outproblem #2. The next 2 pictures were taken with the same exact settings. Excuse the mess in my room.
    00XbG2-296871584.JPG
     
  29. Here is Picture #2 taken with the pop-up flash from the same position with the same exact settings as Picture #1.
    00XbG5-296871684.JPG
     
  30. How do you get a pop-up flash to cast shadows like that? The light source in the second shot appears to be quite a bit to the right of the camera, and indeed appears to be reflected in the TV screen on the left. Is the pop-up flash triggering a studio strobe?
     
  31. How do you get a pop-up flash to cast shadows like that? The light source in the second shot appears to be quite a bit to the right of the camera, and indeed appears to be reflected in the TV screen on the left. Is the pop-up flash triggering a studio strobe?​
    agreed. something is casting light from the right of the frame....
     
  32. "agreed. something is casting light from the right of the frame...."
    Nope, as far as I know there was only one light source the pop-up flash. there are a few possibilites why this might have happened.
    1) The dark picture was taken 15 seconds appart from a previous shot, while almost a minute expired between the dark and light picture.
    2) The pop-up flash did not go off.
    3) The battery was drained and did not fully recycle the flash.
    4) The Auto Lighting Optimizer was set to Enable.
    5) Bad comunication between camera and flash.
    6) The lens blocked off light from the pop-up flash.
     
  33. Look at the shadows in #2 -- behind the lightstand, the bust, on the floor from the right -- there's no way that an on-camera flash produced those shadows. None of the possibilities you listed would account for the direction of the light (and the pop-up flash did go off, it's in the EXIF data).
     
  34. Harry, glad you sorted out one of our problems. I'm not sure what you have going on in the pictures above, but as others have noted it sure looks like you have a strong light source off to the right. Were you using the tilt/shift lens here too? Would you get that view if you had the lens tilted and shifted to one side (making it appear that the flash is not on camera)?
    After going through my pictures again, it appears that I was mistaken. It looked like I had a problem because I had such extreme, progressive changes in images over such a short burst. However, as I examined more of the images I noted that many of them matched the "underexposed" image--it had to do with the direction my camera was facing. And before anyone asks, no I was not using a polarizing filter. I sure am glad to hear that there's no inherent problem with the 7d because in every other area, the thing is rock solid.
     
  35. "Look at the shadows in #2 -- behind the lightstand, the bust, on the floor from the right"
    I forgot to mention I did pull up the shade on the window to the right and since it was early in the morning that might be Sun light coming through the window at an angle. I was using the Tilt Shift lens, but it was set in the Normal position. As far as the Pop-up flash, if you look at the Exif data it shows the flash was enabled in both pictures ?
    The position of the shadow is baffling though and so far I can't explain it. Mark according t the Canon Rep 'CF:' on the top right side of the play back screen means Card Flash as a reminder that a card is inserted in the camera . It sure sounds confusing, I thought it meant Custom Function. In any case I still got allot of testing to do, only got 25 days left before I can return the camera for a full refund or exchange. Thanks for all the help.
     
  36. Your light source coming in from the right is obviously a point source, because the shadows are extremely sharp. The light source is close by, because the shadows in the upper part of the picture go up (look at the shadow of the blue picture and what appears to be a thermostat by the window), and the shadows in the lower part of the picture go down (look at the shadow of the cardboard box on the floor). Light from the sun would be parallel (and probably not nearly so horizontal), so this is from a much closer source. Interestingly, the picture also shows a second set of shadows, and this set is consistent with a pop-up flash. Look behind the bicycle handlebars and the light stand; you can see shadows on the walls directly behind them. The light stand is particularly interesting, as there are plainly two sets of shadows, one to the left, and one appearing as sort of a ghosting on the wall directly behind the light stand. Interesting stuff, but now I'm not quite clear what these pictures are supposed to demonstrate. They are two images taken under wildly different lighting conditions.
     
  37. Mystery solved, as other posters have found: It's completely operator's fault
    #1, the flowers photo: The photos were taken at noon, so exposure set manually at 1/125 iso 100 f14 will give that "normal" shot. The other shots are with P mode and the "operator" can easily make mistake (accidentally or not) to over expose at f4.5 1/50 (please don't ask me how, that's way too easy)
    #2. The bicycle shots, one with the bright light bulb on, the other without. That result is obvious
    #3. It's definitely the operator fault because he was also confused between the sun and a light bulb, and he thought 4pm is in the morning
     
  38. Didnt read all, my excuses, but the camera may accidentetly have been set to spotmetering.
     
  39. "Mystery solved, as other posters have found: It's completely operator's fault"
    John Tran the canon expert has spoken case closed !
     
  40. Harry with TS lenses I suggest that you always check in live view - especially when you use tilt or shift. First it is difficult to really compose a TS shot on a 35mm viewfinder and really see the impact of TS - especially on the smaller / darker Digital viewfinders. Secondly live view really lets you see the exposure. When I use TS lenses I always use live view as well as the viewfinder.
     

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