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Author Topic: Conflicting results between The-Digital-Picture & Photozone  (Read 1169 times)

Sporgon

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Conflicting results between The-Digital-Picture & Photozone
« on: April 08, 2013, 09:53:49 AM »
Is anyone else confused by the apparent differences in resolution tests performed by The Digital Picture and Photozone ?

On TDP's ISO 12233 charts they can show very different results to photozone's MTF graphs.

For example take the 70-300L and 70-200 f4 IS results; two lenses which people looking for a tele zoom are very likely to be having to decide between. Using 70mm as an example, on TDP's 12233 charts the 70-200 is clearly ( pun intended ) way ahead of the 70-300L, I mean it is like night and day, whereas on Photozone's graphs the 70-300L is clearly showing better results.

Another example is the resolution of the 24-105L. TDP clearly shows this lens to be at its over-the-frame best at 70mm / f8, whereas photozone's results do not confirm this - at all. They show it to be better in the 35-50 region.

In 'field' applications my experiences would suggest photozone is giving a truer picture.

Could these differences be the result of copy variances ? if so it is very disturbing for someone wanting to purchase a high quality lens.

« Last Edit: April 08, 2013, 09:55:44 AM by Sporgon »

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Conflicting results between The-Digital-Picture & Photozone
« on: April 08, 2013, 09:53:49 AM »

Mt Spokane Photography

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Re: Conflicting results between The-Digital-Picture & Photozone
« Reply #1 on: April 08, 2013, 11:59:35 AM »
Lens tests only apply to the SPECIFIC Camera model they were tested on.  You cannot compare results taken with different cameras.
 
Are you sure they were taken with the same camera??
 

K-amps

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Re: Conflicting results between The-Digital-Picture & Photozone
« Reply #2 on: April 08, 2013, 12:03:45 PM »
There always is some sample variation. I have used both and both are very Sharp indeed.

You basically have a trade-off between length and aperture, otherwise both are very Quality Zooms.
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Sporgon

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Re: Conflicting results between The-Digital-Picture & Photozone
« Reply #3 on: April 08, 2013, 12:11:06 PM »
Lens tests only apply to the SPECIFIC Camera model they were tested on.  You cannot compare results taken with different cameras.
 
Are you sure they were taken with the same camera??


TDP was on 1Ds Mk 3, photozone on 5D mk2, but I can't see that is relevant, the point is TDP's 'comparitor' shows the 70-200 f4 to be much better. Photozone has the 70-300 just as good at 70mm.

May have misunderstood your post: yes each lens was tested on the same camera body by each site.
« Last Edit: April 08, 2013, 12:20:36 PM by Sporgon »

9VIII

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Re: Conflicting results between The-Digital-Picture & Photozone
« Reply #4 on: April 08, 2013, 04:10:06 PM »
Lens tests only apply to the SPECIFIC Camera model they were tested on.  You cannot compare results taken with different cameras.
 
Are you sure they were taken with the same camera??

If you compare the difference between multiple lenses on each site you can usually see when one is getting significantly different results from the others.
On TDP specifically you can also look at the 200f2 samples for a comparison of all the different bodies.

It looks like all review sites have dud lenses (relatively speaking) in their line-up. Ideally each site would test three or four samples, but that doesn't quite seem to be practical. I always look at as many reviews as possible when considering a lens.
The best example I can think of right now is the Sigma 120-300 f2.8 OS, which scores very highly set to 300mm f2.8 in some reviews, but the TDP sample at that setting looks awful (in the center, the edges are universally bad). Then sometimes lenses that score somewhat poorly on other sites look great on TDP. Again, it looks like there's a lot of variation in both the samples and potentially in the reviewers.
« Last Edit: April 08, 2013, 04:12:40 PM by 9VIII »
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Re: Conflicting results between The-Digital-Picture & Photozone
« Reply #4 on: April 08, 2013, 04:10:06 PM »