April 20, 2014, 04:14:28 PM

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Messages - AlanF

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136
Tamron soft Pit123? That is unfounded, unsubstantiated drivel. Here are the acutance tests done by DxO. The first is the Tamron at 400mm f/5.6 vs the 100-400 at 400 f/5.6. The Tamron is just as sharp in the centre of the field and its sharpness extends more to the edges. This is not just a one-off result, lensrental measurements are in exact agreement.

The second (bottom) is the Tamron at 600mm f/8 vs the 100-400 at 400 f/5.6. The Tamron is as sharp at 600mm as the Canon is at 400 at the centre, and it is much better at the edges.

137
Lenses / lenstip beware!
« on: February 13, 2014, 12:56:34 PM »
I was directed to lenstip via google link and got this warning. Oh dear - I have visited several times directly.

138
The series III Canon extenders will not physically fit onto the Tammy - not that I would really want to use a TC on it. You will have to use a 3rd party TC.

139
Superficially, your upscaled credit card from the 100-400 (x1.5) looks as good as the image from the 300 f/2.8 II plus 2xTC III.
What?!!
Did you look at the image in full view? If you cant see the day/night difference between the 300mm +2xtc and 100-400 upscaled, then you really need some glasses or a new monitor.... ;)
But thats not what I want to show. My question is: is the upscaled 100-400 as good as a tammy can be at 600mm wide open?
I would never replace my 300mm+2x combo with tammy. But can the tammy replace my 100-400mm as a travel lighter/smaller package? For me, it looks like the tammy only gives better results than an upscaled 100-400mm if you shoot at f8. And thats a turn off for me.

You have deliberately edited my post to make it look as if was saying the opposite of what I did. Here is my full post:
Superficially, your upscaled credit card from the 100-400 (x1.5) looks as good as the image from the 300 f/2.8 II plus 2xTC III. That is because you look at the thick black lines etc that dominate. But, look at the elements with fine detail. I have cropped the ACE sections from the image from the 300+2xTC and the (100-400)x1.5, which have fine detail on the black background. You can see that the fine detail is lost in the upscaled 100-400. (Download to see clearly).

Is that an honest thing to do?

Sorry if I offend you.
Your first comment (the one I quoted) was so amazing that I didnt really read the rest, or didnt see your point :D
And I never intend to claim an upscaled 400mm to be comparable to the canon 300mm +2x. If you looked at the image in full screen you should immediately see the BIIG difference. But you obviously did not, hence my comment.

Of course I saw the full image - I posted some crops from it and surely it must be obvious to anyone that to crop you have to download the JPEG, open it in PS or LR etc.

140
Alan, as you move beyond the test charts and such, I'd be interested to hear your thoughts on the more subjective comparisons between the Tamron & Canon combo - things like AF speed, color, contrast, bokeh, and general handling of the lenses.   

Also, I just realized that the Canon has a huge advantage in polarizer use.  I'm sure you can find a big one for the Tamron, but you certainly can't adjust it like you can with the drop in CPL on the Canon.

Mac
The 300mm f/2.8 II is generally considered to be one of, if not the, finest lenses available. It is optically as good as you can get and built like a lightweight tank with phenomenal AF. It is going to remain the main lens for me when I travel in the UK for bird photography. It is so good that something 80% as good will be good enough to give stunning results.  And that is where the a tamron stands.  The  Tamron is easier to handle being 1 to 1.5 lb lighter, depending on TCs, and very nicely balanced.  It is also smaller and fits into a smaller bag, as well as being more versatile. So, it will be my travel lens, and it will give great results and bring much pleasure to many.

I hope soon to use it in real action rather than charts.

141
Lenses / Re: DxO Review of the Tamron 150-600mm f5-6.3 Di VC USD Canon
« on: February 12, 2014, 04:44:47 PM »
The point about variance is well taken. However, Lensrentals actually analysed two copies each of the Tammy and the 100-400.

http://www.lensrentals.com/blog/2014/01/tamron-150-600-telezoom-shootout

They found identical MTFs for the Tammy and Canon at 400mm and f/5.6. It's clear that they are close to being indistinguishable from more than one different testers.


142
Superficially, your upscaled credit card from the 100-400 (x1.5) looks as good as the image from the 300 f/2.8 II plus 2xTC III.
What?!!
Did you look at the image in full view? If you cant see the day/night difference between the 300mm +2xtc and 100-400 upscaled, then you really need some glasses or a new monitor.... ;)
But thats not what I want to show. My question is: is the upscaled 100-400 as good as a tammy can be at 600mm wide open?
I would never replace my 300mm+2x combo with tammy. But can the tammy replace my 100-400mm as a travel lighter/smaller package? For me, it looks like the tammy only gives better results than an upscaled 100-400mm if you shoot at f8. And thats a turn off for me.

You have deliberately edited my post to make it look as if was saying the opposite of what I did. Here is my full post:
Superficially, your upscaled credit card from the 100-400 (x1.5) looks as good as the image from the 300 f/2.8 II plus 2xTC III. That is because you look at the thick black lines etc that dominate. But, look at the elements with fine detail. I have cropped the ACE sections from the image from the 300+2xTC and the (100-400)x1.5, which have fine detail on the black background. You can see that the fine detail is lost in the upscaled 100-400. (Download to see clearly).

Is that an honest thing to do?

143
Lenses / Re: DxO Review of the Tamron 150-600mm f5-6.3 Di VC USD Canon
« on: February 12, 2014, 03:39:30 PM »
DXO:  "......softer across the frame at 600 than the Sigma 150-500 is at 500..."

That's a disappointment since  my experience of the Sigma at 500 was not good.

Being realistic at this price you really can't expect the Tamron @ 600 to be even close to the 100-400 @ 400. That's the difference - the Canon is sharp at the top end but the Tamron ain't. Ah well just have to wait for the new 100-400 and use a TC to get 560 assuming by then Canon can give us a crop camera with f8 AF capability. That maybe is asking a lot.

But then DXO might have tested a sub-par copy........


Did you read:
http://www.dxomark.com/Reviews/Tamron-150-600mm-f5-6.3-Di-VC-USD-Canon-mount-lens-review-New-contender/Tamron-150-600mm-f5-6.3-Di-VC-USD-vs.-Sigma-150-500mm-f5-6.3-APO-DG-OS-HSM-vs.-Canon-EF100-400mm-f4.5-5.6L-IS-mounted-Canon-EOS-5D-Mk-III-Good-overall-IQ

"Against the Canon, the Tamron is, surprisingly, slightly sharper between the 150-300mm focal lengths, though there’s not much in it at 400mm – the Canon is sharper centrally though the Tamron has the slightly better uniformity across the field. However, the Canon has heavier vignetting at 400mm and noticeably more lateral chromatic aberration in the corners.

145
Superficially, your upscaled credit card from the 100-400 (x1.5) looks as good as the image from the 300 f/2.8 II plus 2xTC III. That is because you look at the thick black lines etc that dominate. But, look at the elements with fine detail. I have cropped the ACE sections from the image from the 300+2xTC and the (100-400)x1.5, which have fine detail on the black background. You can see that the fine detail is lost in the upscaled 100-400. (Download to see clearly).

146
Here are the relative aperture sharpness plots from FoCal for the Tamron at 600mm on the 70D (Top) and 5DIII (Bottom). You can see the 70D, if anything, retains its sharpness with aperture better! I did the 5DIII measurements 3 times and got optimal values of f/9/, f/10 and f/11. Keep between f/8 and f/14 for maximum sharpness.

147

Read this:
http://jonrista.com/2013/03/24/the-diffraction-myth/
So, technically speaking, stopping down to f/11 is stopping down to f/11...the ultimate result on IQ in reach-limmited scenarios (same lens, different cameras, same subject distance) is roughly the same regardless of FF vs. APS-C (technically, APS-C would actually have the edge, barring blurring from other factors...i.e. the 7D has a stronger low pass filter than the 5D III, which mitigates some of the benefit of having smaller pixels, but not entirely.) Smaller pixels will always give you a cropping advantage, and the more you stop down, the returns offered by those smaller pixels simply diminish until they offer no benefit over larger pixels (but at no point would smaller pixel EVER be "worse" than larger pixels from the standpoint of diffraction...noise is another matter.)


Jon
Beautiful webpage - thanks for the link. The so-called diffraction limit isn't a hard barrier but lowers resolution slowly as the aperture is narrowed through it. To reinforce and paraphrase what you have elegantly argued, at wide apertures, the crop sensor of the same number of megapixels as FF gives better resolution than full-frame because the pixels are 1.6x1.6 times smaller. But, when the disk of light caused by diffraction is larger than the pixels, the size of the disk limits resolution and the crop loses its resolution advantage.

148
Thanks for showing, also for the 400mm upscaled :)
For me the tammy looks not good at 400mmf5.6. The Canon 100-400mm is clearly better here than your tammy results.
According to DPR the 100-400mm@400mmf56 has about same sharpness as 300mm +2x@f56 as shown here:
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=113&Camera=453&Sample=0&FLI=7&API=0&LensComp=739&CameraComp=453&SampleComp=0&FLIComp=2&APIComp=0
And this correspond to my findings.
Based on this I downscaled your C600f56 to 400mm (66.67%) to give a similar output as expected from 100-400mm. Then I upscaled the result by 45% to simulate an upscaled 100-400mm.
In this case the 100-400mm clearly outperform the tammy at 600 f6.3.  ;)
See enclosed image.
So I'm still not convinced that the tammy will be worth an upgrade from 100-400mm.


1. You wrote when I asked you to compare my photos for with your own: "In that case I need to copy your exact distance, camera, camerasettings and PP settings as well." and "And printouts for test purpose? I dont find that to be suitable for high res comparisons."
You are therefore contradicting yourself as you have done precisely what you said shouldn't be done. Your manipulations by downscaling I think are meaningless.
2. You have also written: "I guess an upsampled tammy 400mm shot will show same or more details than tammy on 600mm wide open." The images I have posted show that your guess is wrong.

The only valid comparison for you to do is to compare your 100-400L directly with a Tamron under the same conditions, as you indicated. Lensrentals has done precisely that with two good copies of their 100-400 and two copies of the Tamron. They have virtually the same resolution measured by very careful Imatests.

http://www.lensrentals.com/blog/2014/01/tamron-150-600-telezoom-shootout

If you don't believe them, well that is your decision.

Added note: You edited your post after mine was first written, removing an uploaded image, and your original post is in my reply above. You have removed what I criticised. Do I now take it that you have withdrawn: "Based on this I downscaled your C600f56 to 400mm (66.67%) to give a similar output as expected from 100-400mm. Then I upscaled the result by 45% to simulate an upscaled 100-400mm.
In this case the 100-400mm clearly outperform the tammy at 600 f6.3.  ;)
See enclosed image. "


149
Charts and real world are two different things but it kinda looks to me like the 300 2.8 with 2x turns in a bit better resolution the the Tammy at 600.  But, the cost of the Canon is about 6x the Tammy.  Tough call.
Alan, thank you for the excellent tests and I agree with JPAZ that Canon combo does resolve better, but only when truly pixel peeping.  For the money, the Tamron is a fantastic lens, and if the IS, AF, and durability is decent, it's an absolute steal over the Canon combo that we both own.  I won't be selling my 300 f/2.8 IS II anytime, but I could see myself using the Tamron for travel, for situations where the 300 simply isn't practical, and anytime the advantages of having zoom would outweigh the Canon combo.

The Canon combo does, of course, have the edge, and I love it. But, as you say, the Tammy is going to be my travel lens, and that is not damning it with faint praise - it is a very good lens indeed, and easier to tote around.

150
At 600mm the lines are well resolved at both f/5.6 (top) and f/8 (middle). The f/8 is a much better image. At the bottom is 600mm from the 300mm f/2.8 II + 2xTC III at f/5.6.

The difference between the Tammy at f/8 and the Canon at f/5.6 is not night and day, as claimed. And, the 400mm up sampled is not as good as the Tammy at f/6.3.

The focus was much quicker in use today with the limter set to 15-infinity and in good light. The problem with autofocus on older Canons is the fault of Canon as I have problems with their own lenses on the 7D, but not the 70D or 5DIII.

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