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Author Topic: Canon 50d question  (Read 2196 times)

Greg D

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Canon 50d question
« on: January 19, 2009, 11:53:55 am »

I'm considering a 50d and have one main hesitation.  How do those of you who've used them cope with the reduced range of usable apertures?  (Now, I know someone's going to correct me and tell me diffraction has nothing to do with the sensor.  But higher-resolution sensors do SHOW diffraction sooner, correct?  That's been my experience moving from 8 mp to 10.)  I shoot mostly while hiking and carry smallish lenses, so largest apertures are 3.5 - 4.  If diffraction starts to show at f8 (as reviews I've read indicate), that doesn't give much room.  Not a problem when shooting large vistas where hyperfocal is reached with larger apertures, but when shooting something deep and relatively close (say a cascading stream in woods), seems like it would be.  Yes or no, and what do you do about it?

Thanks................
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fike

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Canon 50d question
« Reply #1 on: January 19, 2009, 01:54:12 pm »

I can't honestly say that when I have been in the field I have paid any attention to the effect.  I can't honestly say that I have come back to the studio and looked at my images to disappointedly think "gosh, if only I had two more stops of aperture."  I know some people are that analytical about their photography, but I am not.  Honestly, I fail to see how you can shoot landscape in the field and notice these types of subtlety on the 50D.  

Whether the effects of diffraction set in at f/8 or f/11, you still get more detail even at f/11 than you had on the 30d or 40d.  It isn't dramatically more detail, but I don't believe that has been disputed.

My opinion is that the effect is largely one that is noticeable in the lab and practically irrelevant in the field.  With that said, I don't think we will be able to expand the Megapixel race on the APS-C sensor and continue to increase visible resolution.  It is just barely noticeable now, but add more pixels and it will be more pronounced at 100% magnification.  12-14 MP seems to have been the sweet-spot that Canon passed with the 50D.
« Last Edit: January 19, 2009, 01:54:55 pm by fike »
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Ralph Wagner

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Canon 50d question
« Reply #2 on: January 20, 2009, 09:28:16 am »

I have studied this to some degree. You will see diffraction sooner on a monitor rather than in prints. And even here you have to pixel peep to see it. I have just started using a 50D and I haven't had first hand experience with all the different aspects of its use. I can tell though that I have seen some large prints (up to 16 x 24) made from a 50D at f8 and I think diffraction is the least of your worries. The prints simply looked great.
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Ralph

sanking

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Canon 50d question
« Reply #3 on: January 23, 2009, 11:47:46 pm »

I have a Canon 50D and have tested several lenses (including a number of primes as well as a few L lenses)  with  a resolution target. While best resolution is  at an aperture of about f/8 - f/9, results at f/11 were close  and even f/16 did not fall off all that much. F/22, however, was fairly dismal.

The main issue with the 50D is that to fully take advantage of 15 mp on an APS sensor  you need to be  using the best lenses possible. Most of the Canon zoom lenses are simply not up to delivering the 90+ lines per millimeter that the sensor is capable of capturing.

In other words, the quality of the lens  you use on the Canon 50D is, in most cases,  more inhibiting to sharpness than diffraction limited aperture. Consider buying a few prime lenses for the 50D.

Sandy King




Quote from: grog13
I'm considering a 50d and have one main hesitation.  How do those of you who've used them cope with the reduced range of usable apertures?  (Now, I know someone's going to correct me and tell me diffraction has nothing to do with the sensor.  But higher-resolution sensors do SHOW diffraction sooner, correct?  That's been my experience moving from 8 mp to 10.)  I shoot mostly while hiking and carry smallish lenses, so largest apertures are 3.5 - 4.  If diffraction starts to show at f8 (as reviews I've read indicate), that doesn't give much room.  Not a problem when shooting large vistas where hyperfocal is reached with larger apertures, but when shooting something deep and relatively close (say a cascading stream in woods), seems like it would be.  Yes or no, and what do you do about it?

Thanks................
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