BluesWest wrote:
Did you microadjust the AF for each extender/lens combination? If not, your test is meaningless.
John
From the original post.
USAF 1951 target resolution tests, 1DsIII 70-200/2.8L IS Mk II, ISO 800, yes MLU, no IS, geared head on tripod. Results include both manual focus using LiveView (LV) and autofocus (AF) in One Shot mode with centre AF point active. Results are shown for both wide open and one stop down (i.e. f/4 and f/5.6 for the 1.4x Extender, and f5.6 and f/8 for the 2x Extender).
Microadjust does not matter if you use manual focus.
BluesWest:
Did you microadjust the AF for each extender/lens combination? If not, your test is meaningless.
John
I'll apologize for him: "Okay, I was wrong, and I'm sorry. Upon further (any?) reflection, it occurs to me that, even if my unstated assumption was correct (namely that one or more of the OP's camera/lens combos would benefit from MF adjustment), I must admit that it would still only render one aspect of the test less meaningful. What I meant to say was that I appreciate his considerable effort at trying to provide useful information to the group."
These comparison's you have done are quite detailed.
Though I am pretty sure I am in the minority, I am extremely pleased with the quality (sharpness & detail) of the results from both my 1.4x II & 2x II TC's.
Thank you very much for providing this detailed comparison. Looking at your results I would say that the differences, while observable, are small enough that I feel little compulsion to trade my 2xII for a 2xIII. In particular, when using a 2x on a long tele I am almost always primarily concerned with the center of the image. The relatively subtle improvements your test shows are most pronounced at the edges of the frame - where I need them the least.
Regardless, thanks again for providing us all a clear comparison.
Jim, this test has sold me on the 2xTC III. The contrast and clarity improvement all over the frame makes for a higher quality image visible at all sizes, not only when pixel peeping at 100%.
AGeoJO wrote:
Jim,
Thank you for pointing those differences out to me. Yes, I do see the difference now. They don't jump right at you at based on the images scaled for the web.
Joshua
Just for clarity, the images labeled at "100%" have not been "scaled for the web" - barring changes due to browser/monitor calibration for color, you are seeing the same original on screen at full size as Jim saw.
I see a bit more contrast but not more "sharpness" and a bit better CA. These are so slight there are well within PP limits. After CA and contrast adjustment in PS, I wouldn't expect any difference. So I'm not sure if it is worth the price difference to many.
But faster AF (especially with "unobtanium" Mk III Great Whites) is quite another matter and could be the make or break for sports/action photographers.
SoundHound wrote:
I see a bit more contrast but not more "sharpness" and a bit better CA. These are so slight there are well within PP limits. After CA and contrast adjustment in PS, I wouldn't expect any difference. So I'm not sure if it is worth the price difference to many.
Contrast enhancement in PP also enhances noise. Better contrast SOOC is equivalent to being able to shoot at higher ISO, in other words effectively a faster lens. Given the huge cost of extra speed with superteles, the price difference between the two TC versions seems tiny in comparison.
Anyway, thanks for the comparison. I've been wondering what the difference was, this test has nailed it nicely.
I doubt the differences would show up on a small print, but an enlargement or heavy crop, which I do sometimes, would show up the differences considerably.
What was a "normal" price for the 2x III? I use the 2X II on my 200L f2 and really like the results but for what it is, if I can eek out even more it is worth the expense with this lens.
My experience with PS is that a bit of "Clarity" (a form of "local contrast") and, certainly CA adjustment won't show with "in the ballpark" exposed captures. Yes if you are paying $4K+ for a great white then why not spring for a Mk III. But if you already have your Mk II then it becomes why change over if I am correcting the image to suit in my workflow?
When I bought my second 200mm F2.0 (a Nikkor) I "only" spent $3700 for a minty Mk I instead of $6000 for the new Mk II. Later I coupled it with a 1.7x TC-and the 2.0 TC Mk III. Anyway much of this may be academic since the product pipeline is emptying and it will take a lot of time before post quake Japanese product is shipped.
I agree that the effect of post-processing is small and I am not in for an argument, I just want to elaborate a bit.
From the "painting" example in this thread, local contrast adjustment with about 15% USM with a suitable radius is about what you need. If you use 50% USM with the same radius, you can see an increase in noise similar to a full ISO stop. So the effect can be quantified to about 1/3 stop.
This test does not show comparisons at incremental 1/3 aperture stops, but the samples at TDP indicate that for sharpness and local contrast, the new TC is as good stopped down 1/3 stop as the old one is stopped down 2/3 stops. Another indication of the magnitude of the improvement.
As for CA correction, it is my experience that images that are CA corrected in software have less resolution and actuance than images with no CA to begin with.
I just picked up a 2XIII for my 300 2.8IS. I've been reluctant on spending the $ on a 2X, but the positive reviews tempted me. I tuned the MA a day or two ago on my 7D and was eager to try the set up on some "live" target shots. When I got home tonight, this passer byer became "Prime Supsect".
Nothing special was done here in pp, just a tad bit of crop to show the detail and my typical sharpening. I left the exif intact.
300 2.8IS, 2XIII, 7D / f5.6, 1/125 ISO 500 on a stick. For me, although nothing special, just testing the detail ability of the 2X, I have to admit...I'm pretty pleased.
That looks OK, Jim, given the adverse atmospheric conditions.
No.1 is clear enough just that those animals are quite distant. What kinda seals are they ?
