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  1. #21
    Join Date
    Dec 2007
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    Quote Originally Posted by coldrain View Post
    The Nikon D40 (and D50) are geared towards the "point and shoot" crowd in standard JPEG output. To get the same with your 400D, bump up the sharpening, the saturation and the contrast on the 400D.

    In situations like that dull outdoor pic you showed, the Nikon lens will do a bit better... it is a tad more contrasty and a tad less CA prone. But, if you stop it down to f8 your results will be better.

    So, yes, part of it is settings, and a part or it is the lens. But in better conditions and more interesting subjects, the results will be better.

    Try the new Canon 18-55 f3.5-5.6 IS, it is very sharp and will give you IS to boot.
    Thanks coldrain,
    I have taken additional set of photos in which I increment the 400D's contrast, sharpness and saturation as you mentioned, and yes, I can get images that look as good as the D40 sometimes. Occasionally I even get a few that look better, but in general the Canon does not look as good. Yes, the wide outdoor shots all go to Nikon I assume due to the lens as you mentioned, but sometimes the indoor shots are better with the Canon. The Canon seems to have trouble with its light metering of the scene. Shots are frequently underexposed without human intervention.

    Next I moved to another set of experiments where I take a series of indoor pictures with the Canon set at 0, +1/3, +2/3, and +1 ev and look for the best (yeah, the bracketing feature comes in *real* handy here!) I find that the amount of exposure compensation required varies from shot to shot, so no one value works for most pictures (no surprise I suppose). The end result is that if I am willing to fine tune the contrast, sharpness, saturation and exposure compensation for each shoot I can get shoots with the Canon that look as good as the D40 about half of the time. I guess if you shoot RAW and post process you can remove most of this fiddling from the camera and just rely on doing it on your computer, but if you want to capture jpegs, looks like Nikon has made some better choices in their onboard algorithms imho.

    So in summary so far I see 3 reasons why the Nikon is looking better than the Canon in my inexperienced hands.

    (1) The Nikon has a better kit lens.
    (2) The Nikon seems to have a smarter metering system and has made some better choices in the settings of their image processing algorithms for jpeg captures.
    (3) The Nikon has a more linear sensitivity to light over its dynamic range. You can read about this in the following links. These plots show that while the Canon has a slightly wider total dynamic range, the upper end of the Canon curve is highly nonlinear and compressed, which introduces distortion. The Nikon curve is nicely linear up to the point where it clips (which also introduces distortion, but a different kind that may or may not be less noticeable depending on what you look for in the picture). It might be better to have a linear response up to +3ev rather than a non linear response that extends further. Not sure how much this will really impact our visual perception of IQ though, which after all is all that really matters.

    http://www.dpreview.com/reviews/nikond40/page18.asp
    http://www.dpreview.com/reviews/canoneos400d/page19.asp
    Last edited by rpauls; 12-21-2007 at 08:34 AM.

  2. #22
    Join Date
    Mar 2007
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    I'm trying out auto ISO with a max sensitivity of 400 and a min shutter of 1/30. I had been thinking about this for a while. However, I'm thinking I'll be setting ISO manually most of the time. If you want to go with an automobile example, auto ISO is like an automatic transmission; it works and is easier on you, but it's sure not going to give you the best possible performance.

    I do agree about the D40 metering; it's very accurate with the occasional exception of overexposing. For many this isn't a problem, but I don't like seeing any blown highlights in my photos. Probably a result of being competent with post-processing; I can lighten shadows, but I can't fix what's not there in highlight detail.

    The Canon tends to underexpose a little (probably to protect the highlights, actually), coupled with a very cool color tone which it seems to prefer. Of course one can always change a thing like that, but many feel that Nikon has more pleasing colors straight out of the can.
    Nikon D40 + kit lens

    Nikkor 50mm f/1.8 D AF(...or not)

  3. #23
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    Dec 2007
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    24

    Canon waranty fix for underexposure problem in 400D XTi (before/after shots)

    Well it looks like I found the problem. A simple google search revealed tons of articles describing problems with the Canon XTi underexposing. AND people are sending their cameras back to Canon and getting them FIXED by Canon. For an example look at the link below which shows before and after pics with the Canon 400D XTi. The most interesting thing to me with this set of pics is that after Canon fixed the underexposure problem, the EXIF data shows the new shots are not using either a slower shutter or a larger aperture, and the ISO is the same, yet they are much brighter. This means that whatever Canon is fixing is different than simply turning up the exposure compensation to +2/3 or so, which would of course then change either aperture and shutter in order to get more light.

    So it turns out what I am seeing is not user error, but a defect. They say it was designed this way to preserve highlights, but the fact that they're fixing it would seem to acknowledge that it's a defect. Now, if only I had a "good" 400D to try to se if it looks better than the Nikon D40. I'll bet it does, but I am hesitant to buy one that has a known problem and immediately send it in to be fixed. Maybe I'll try a few more in stores.

    This really stinks, I was all set on the D40 since it takes superior pictures, but now I find I may be better of buying a defective Canon.

    Here's the link:
    http://www.pbase.com/jrmiami/canon_f..._underexposure

    Have you guys heard about this? The article I am quoting is several months old. Has Canon issued any firmware patch for this? Have they since fixed the defect in recent product?

    Thanks,
    Rich
    Last edited by rpauls; 12-23-2007 at 09:41 PM.

  4. #24
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    i'd imagine the ratio of defective users VS defective cameras is probably about 1,000,000 - 1.
    D800e l V3 l AW1 l 16-35 l 35 l 50 l 85 l 105 l EM1 l 7.5 l 12-40 l 14 l 17 l 25 l 45 l 60 l 75
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  5. #25
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    Jul 2005
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    Your XTi is clearly not "defective" nor "underexposing, there is almost no difference on the samples you posted.

    We already discussed things, that the XTi in standard settings does less contrast/sharpness/saturation enhancing.
    Also we talked about that the Canon kit-lens you have performs a little less than the Nikon you have, especially in shots like the ONE example you showed.

    There is nothing wrong with your XTi as far as we can see, and the slight difference in exposure is so slight, you can see the same difference in multiple shots taken by one camera (and your composition is not even the same in both shots).

    So, either drive yourself crazy, or just explore your cameras better. Shoot RAW in both, use the same RAW converter for both, and you will see just how comparable the cameras are without the manufacturer default settings clouding your perception.

    And if you want to be happier with your XTi when pixel peeping, get at least the 18-55 f3.5-5.6 IS.

    Of course, if you are incapable ofsetting the 400D/XTi to your taste, then just keep the Nikon D40 and learn to live with its quirks.
    But no, there is nothing wrong with 400D/XTi's in particular, and yours is not defective or severely underexposing.

    Like Fion mentioned above.... the D40 over exposes a little bit, the XTi tends to expose quite spot on or sometimes a little under.
    Canon EOS 350D, Tamron SP AF 90mm F/2.8 macro, Sigma 18-50mm F2.8 DC EX, Canon EF 70-200mm f/4 L USM, Tokina AT-X124 Pro 12-24mm F4, Soligor 1.7x C/D4 DG Teleconvertor, Manfrotto 724B tripod, Canon Powershot S30

  6. #26
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    Dec 2007
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    I only posted one picture from the Canon, and I chose one that appeared equally exposed to the Nikon because I was looking at other acpects of IQ, i.e., whether or not the kit lens was as good.. So, yes, I agree the image I posted does not show an underexposure problem, but there are many more images that do. And what I suspect now, is that the other issues I am seeing (focus problems, sensor noise, edge and color processing) which are all worse on the Canon may be related to the metering system messing up the exposure.


    I think the fact that Canon admits there is a problem and is fixing the cameras and the repaired cameras are exposing more brightly at the same shutter, aperture and ISO settings is ample evidence that the problem is real. I don't think there is any debating this.

    Look, I don't want to belabor the point on this thread, so I will not post anymore on this topic here lest I further wear out my welcome;-) I'd feel the same way as you guys if I were the expert and some new guy came in saying "Canon has a defect". Of course you should suspect that I am simply not using the camera right. Experts will have no problem working with this camera even with the exposure problems it has. I am not trying to change your mind regarding the XTi, I am more interested in reaching other beginners who may be experiencing this or who may be considering purchasing this camera. And since the title of this forum is "Which camera should I buy", I thought this information would be useful.

    I would encourage anyone interested in the XTi to do their own comparison tests and make their own decissions. Take a set of identical shots with the same settings on each and see what you get.

    Thanks,
    Rich

  7. #27
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    Jul 2005
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    Don't lets us keep you from posting, we just react to the info you give us.
    Why don't you post some samples of the underexposed phtos, so we can see what goes wrong?

    There is no under exposing problem with the XTi/400D in general, which does not mean that there may be some actually defective XTi's that do under expose. So, if you can, post some photos.
    Canon EOS 350D, Tamron SP AF 90mm F/2.8 macro, Sigma 18-50mm F2.8 DC EX, Canon EF 70-200mm f/4 L USM, Tokina AT-X124 Pro 12-24mm F4, Soligor 1.7x C/D4 DG Teleconvertor, Manfrotto 724B tripod, Canon Powershot S30

  8. #28
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    Dec 2007
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    sample images

    OK. Here are a few images illustrating the underexposure problem. The first is from the Nikon D40 and the second and third are from the Canon 400d XTi. Not sure if the EXIF data will still be readable from the jpegs so here is the basic data:

    1st
    D40 in Aperture priority
    1/1600, f3.5, iso200, 0ev

    2nd
    400D in Aperture priority
    1/2500, f3.5, iso200, 0ev

    3rd
    400D in full manual (to match D40 shutter speed)
    1/1600, f3.5, iso200, 0ev


    The Canon underexposed when left to its own meetering in Av mode by choosing the 1/2500 shutter speed rather than the 1/1600 of the Nikon, then I manually set the Canon to 1/1600 and took another picture. Now the exposure is about equal, however, the quality of the Canon pic is significantly worse than the Nikon. If you zoom in you will see it is less clear adn appears distorted -- also a bit softer, and of course the colors are cooler, but I try to ignore this. If I look at darker scenes there is also more noise in the Canon shots, but this shot is so bright the noise is not visible. It is easy to see on the full resolution files I have but I am not sure if this will be captured in these highly compressed jpegs since I am only alowed to post 200K files here. I could send 100% crops if anyone is interested or I will mail the originals.
    Attached Images Attached Images    
    Last edited by rpauls; 12-25-2007 at 06:56 PM.

  9. #29
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    Jul 2005
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    Well... your XTi definitely does not malfunction.
    The D40 photo and the 2nd XTi photo are clearly over exposed. Look at the center bushes, the green and the red are just too light.

    The XTi is more spot on in that area. So, the XTi exposes slightly conservative, and the D40 exposes over. So yes, there will be a difference.

    You, the user, are in command though. If you like over exposed, then just correct the exposure. You can have your XTi over expose to your liking standard, for instance. Or you can set the exposure yourself to your liking with every shot, by metering on what YOU think is a mid tone and would give a correct exposure with spot metering.
    To set it to over expose, put it in Av mode, press the Av+/- button, and turn the wheel to have it +1/3, +2/3 or +1 Ev extra exposed to your liking.

    But fact is... your XTi does NOT show any exposure defect, the point and shoot character of your D40 just has you go wow (with its over exposure, extra saturation and extra contrast/sharpening in JPEG).
    Neither of the photos is exposed correctly, but you can't expect a camera to actually know what is the correct exposure... it remains guesswork for the cameras.

    So.. either set your XTi up to your liking and get another lens like the 18-55 IS or Sigma 18-50 f2.8 EX DC Macro, or get used to the D40's quirks in handling and menus.
    Canon EOS 350D, Tamron SP AF 90mm F/2.8 macro, Sigma 18-50mm F2.8 DC EX, Canon EF 70-200mm f/4 L USM, Tokina AT-X124 Pro 12-24mm F4, Soligor 1.7x C/D4 DG Teleconvertor, Manfrotto 724B tripod, Canon Powershot S30

  10. #30
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    Dec 2007
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    24

    histograms for the above images

    I can certainly appreciate that the exposure setting is a matter of personal and artistic preference, so it is possible that some people may prefer the exposure of the canon 400d, and other the nikon d40, but my "guess" is that most would prefer the nikon. I would like to hear input from others as to what they feel looks best to their eye.

    Then in addition to the subjective evaluation of exposure, there is also the histograms to consider. I am attaching the histograms for the first two pics. Do you think that the histogram for the d40 is indicating overexposure? Why is there so much unused space to the right of the Canon histogram? Doesn't this indicate the image is underexposed? My opinion (as a newbe) was that the nikon is making better use of its available dynamic range. What do you guys think?

    Thanks,
    Rich
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