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Thread: How accurate is the MTF chart

  1. #1

    Wink How accurate is the MTF chart

    Hi,

    I was browsing the Nikon website and noticed that some of the chart showed poor performance of the lens in terms of the Bokeh and maybe sharpness.

    Somehow, base on the usage, a combination of the body and lens; Nikon yield great IQ.

    Even as compared with another maker; their MTF chart that is suppose to be of a better performanced lens as compared to an identical focal length is just as good.

    How do they actually view or present the MTF chart and if the different manufacturer adopt the standards differently?

    Some friends disregard these readings and commented it is a waste of time and just something written up to boost more "confusion" that's all.

    What's your opinion on this?

  2. #2

    Default Re: How accurate is the MTF chart

    Maybe you can provide some examples of lenses for reference?
    Everyone has different level of expectations versus the prices they pay for the lens.
    Kent Wong Photography |Leica Q & Leica M-P 240 | 75 & 28mm Summilux

  3. #3

    Default Re: How accurate is the MTF chart

    it's actually quite consistent with what I've seen and tested.
    of course MTF given in canon and nikon websites are for designed lens, and actual production and sample variation will ensure that their performance will be slightly worse than the ideal chart.

  4. #4

    Default Re: How accurate is the MTF chart

    Photozone.de and dpreview are trustworthy places. Most of the time I find photozone.de reviews accurate. But take notes of sample variations which result in some unncessary whining.

    Bottom line: don't get too obsessed about sharpness, decent sharpness is good enough. There are more things about a picture than just sharp sharp sharp

  5. #5

    Default Re: How accurate is the MTF chart

    OT a bit, but I think another very important thing about a lens is the focusing speed and reliability, especially in low light. Most reviews don't comment on that because they don't use the lens a lot in an actual shooting scenario. They just say something like "this lens uses Sigma's HSM motor and focuses reasonably fast, taking xxx seconds to rack through the focus". This is a typical focus speed test that doesn't really tell you anything. In low light, no matter how fast your lens racks through the entire focus range, if it hunts and is unable to lock focus or just randomly locks on to something that is not what you selected, it still has a problem with AF.

  6. #6
    Senior Member ovaltinemilo's Avatar
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    Default Re: How accurate is the MTF chart

    I always look at MTF given by the same reviewer on 2 different lenses if I were to compare them. It's quite a good guideline. By the way, it's always good to compare MTF generated under same condition, same test camera, same scene etc for best accuracy...
    ...:::..::.Nikon.::.:::..
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  7. #7

    Default Re: How accurate is the MTF chart

    Quote Originally Posted by kentwong81 View Post
    Maybe you can provide some examples of lenses for reference?
    Everyone has different level of expectations versus the prices they pay for the lens.
    Erh....maybe...say just grab one good lens from Nikon and Canon. Our 24-70 was commented as a better lens than the Canon 24-70. But not necessary so if we are to compare the charts base on my re-collection of both the charts.

    Other is the 50mm f1.4 prime or both the makers.

  8. #8

    Talking Re: How accurate is the MTF chart

    Quote Originally Posted by brapodam View Post
    OT a bit, but I think another very important thing about a lens is the focusing speed and reliability, especially in low light. Most reviews don't comment on that because they don't use the lens a lot in an actual shooting scenario. They just say something like "this lens uses Sigma's HSM motor and focuses reasonably fast, taking xxx seconds to rack through the focus". This is a typical focus speed test that doesn't really tell you anything. In low light, no matter how fast your lens racks through the entire focus range, if it hunts and is unable to lock focus or just randomly locks on to something that is not what you selected, it still has a problem with AF.
    I agree with your deduction that the AF speed and accuracy is important. However, not all would rely much with the lens during low light am I correct? We can always fall back on using a tripod and strobes.

    Wonder why did they not include it as a comprehensive table make our life so much easier.

  9. #9

    Default Re: How accurate is the MTF chart

    Quote Originally Posted by dmjunkie View Post
    I agree with your deduction that the AF speed and accuracy is important. However, not all would rely much with the lens during low light am I correct? We can always fall back on using a tripod and strobes.

    Wonder why did they not include it as a comprehensive table make our life so much easier.
    If you're an event shooter, a lot of time you'll be shooting in low light. If you're shooting your kids at home running around, AF speed is crucial. There are a lot of people who claim that the Tamron 17-50 f2.8 is quick to focus, but I have tried it on my cousin who was running around the house, and I have been frustrated by the AF which could not lock focus 90% of the time.

    For fast aperture lenses, AF speed is very important as it is probably going to be used in low light situation. For UWAs or macro lenses focus speed may not be very important, but for f2.8 zooms, I feel AF speed is even more important than sharpness.

  10. #10

    Default Re: How accurate is the MTF chart

    Quote Originally Posted by brapodam View Post
    If you're an event shooter, a lot of time you'll be shooting in low light. If you're shooting your kids at home running around, AF speed is crucial. There are a lot of people who claim that the Tamron 17-50 f2.8 is quick to focus, but I have tried it on my cousin who was running around the house, and I have been frustrated by the AF which could not lock focus 90% of the time.

    For fast aperture lenses, AF speed is very important as it is probably going to be used in low light situation. For UWAs or macro lenses focus speed may not be very important, but for f2.8 zooms, I feel AF speed is even more important than sharpness.
    I saw the pic produced by my buddy on his tamron 17-50 VC for a fashion show which looked very decent. You might want to consider a prime lens to do the work. They are fast and usually accurate to the dot.

  11. #11

    Default Re: How accurate is the MTF chart

    Quote Originally Posted by dmjunkie View Post
    I saw the pic produced by my buddy on his tamron 17-50 VC for a fashion show which looked very decent. You might want to consider a prime lens to do the work. They are fast and usually accurate to the dot.
    Fashion shows usually have lights pointing at the model, so focusing isn't a problem. The models don't run around either. Any lens could do the job.

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