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70-200GM; Please help me reach a verdict
  
 
Mark_EL
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p.1 #1 · p.1 #1 · 70-200GM; Please help me reach a verdict


Alright, today I traded my Canon 70-200 f2.8 II + extender (plus a heap of cash) for a brand new Sony FE 70-200 f2.8 GM. However, paranoid as I am (since I've been reading a lot of stories about decentered copies out there) I decided to do a test.

Now, I am not sure I tested it the right/ best way. But I have the result here and I have a feeling that the left part is just that bit softer then the right. Can you people with more knowledge about this stuff please help me reach a verdict? Is my copy performing as it should be, for a 3000 Euro lens? I must say that the center sharpness looks fine to me... just that left side that worries me a bit. Or are perhaps my expectations set too high?

Because of the enormous large file, you can look at the full size here:

https://c1.staticflickr.com/5/4337/36724385933_7c708aafe0_o.jpg


This was the way my test was setup:













The test chart are four A4 prints on normal office paper, stuck together with some tape on the back side. As you can see I used a spirit level to make sure my camera was perfectly aligned. And instead of a normal tripod I used a fairly heavy (about 35 kilograms) Cambo mono stand.

I used CaptureOne Live View to manual focus on the chart. The OSS was turned off, ISO was set to 400, Custom WB, 2 sec timer on the shutter and I took the shots by using a remote....



Sep 29, 2017 at 06:02 PM
DaveBurbank
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p.1 #2 · p.1 #2 · 70-200GM; Please help me reach a verdict


I'm not an "expert" but here are my thoughts:

I sold the same Canon lens and bought the same Sony lens. I'm loving the Sony. I haven't done any tests like you. I shoot with the lens and love the images.

Do you say anywhere what your aperture or shutter speed were?

Your test image looks pretty darn good to me. Since you're so far from the test chart and since the paper was taped to the floor (and not the base of the stand) and since your shutter speed is unknown even the slightest movement could result in a soft image. But I think your image looks good.

Get out the enjoy that lens.



Sep 29, 2017 at 06:39 PM
Mark_EL
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p.1 #3 · p.1 #3 · 70-200GM; Please help me reach a verdict


Thx for looking Dave. This shot was taken at 200mm, f2.8, 1/30 shutter speed and ISO 400. I used the relatively heavy monostand and the 2 sec timer, combined with a remote shutter to prevent any movement.


Sep 29, 2017 at 06:57 PM
AGeoJO
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p.1 #4 · p.1 #4 · 70-200GM; Please help me reach a verdict


What will you be using the lens for? I hope not only for test charts in future . Seriously though, the so called decentering issues are more for 35mm lenses or wider. Longer focal lengths lenses generally are not designed to take flat images in real life, unless you are in to reproduction of art pieces and for that macro lenses will be better anyway.

I have had and enjoyed my GM 70-200mm lens but mostly I used them for portraits and landscape (for compressed perspective/view) and any other than flat objects. However, if you really want to find out whether your lens is centered, it is fairly easy to do.

You mount the camera/lens using the lens foot on a sturdy tripod in a horizontal format. You aim at something flat, like a block wall (some people frown on this) and set it as perpendicular as possible (although it is not that crucial as you will see later). You focus carefully on the center point, and take 3-4 images using an aperture f/2.8, f/4 and f/5.6 or even at f/8. Without changing the position and focus distance or anything else, flip the camera upside down via the lens collar. Take the same set of aperture range. And compare the images in your monitor. So, the area what is taken with the left side of the camera in the normal position is now taken with the right side of the camera in the flip position. A comparison between the two sets should give you a good idea of centering aspect of the lens. Technically, it can be done with the upper and lower but due to the rectangular format of the sensor, it is less pronounce hence we pay more attention to the left or right side only.

Hope this helps but seriously, go out there and use the lens as you envision of using the lens and enjoy photography and don't dwell too much or too long on testing lenses.

Joshua



Sep 29, 2017 at 07:02 PM
Mark_EL
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p.1 #5 · p.1 #5 · 70-200GM; Please help me reach a verdict


Lol, most definitely not buying this stuff for test charts. I almost never do these kind of tests. But I was a bit scared of buying this lens because of a (bad, or at least less then stellar?) reputation. After all, it is the most expensive lens I've ever bought ;-)


Sep 29, 2017 at 07:08 PM
AGeoJO
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p.1 #6 · p.1 #6 · 70-200GM; Please help me reach a verdict


Mark_EL wrote:
Lol, most definitely not buying this stuff for test charts. I almost never do these kind of tests. But I was a bit scared of buying this lens because of a (bad, or at least less then stellar?) reputation. After all, it is the most expensive lens I've ever bought ;-)


Great! I knew you didn't . And I understand your situation though. I am on the other side of the pond and the return policy of some big stores here is pretty liberal. So, here we can feel a little bit at ease purchasing expensive camera gear since we can return/exchange it without hassle.

BTW, here is a link of a post in the big FE thread showing an image taken with that lens at 200mm and at wide open aperture: http://www.fredmiranda.com/forum/topic/1255248/2444#14199595. And that is one of the few that I posted already and I will have several more.



Sep 29, 2017 at 07:18 PM
gocolts
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p.1 #7 · p.1 #7 · 70-200GM; Please help me reach a verdict


I posted a 100% crop of my FE 70-200 2.8 at 200mm & f/2.8 as well (see below). I've also had good luck with the lens.

http://www.fredmiranda.com/forum/topic/1503419/1#14140277



Sep 29, 2017 at 07:42 PM
SoundHound
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p.1 #8 · p.1 #8 · 70-200GM; Please help me reach a verdict


I have read a lot of comment about this lens. Speculation exists that at infinity and 195-200mm that there are deficiencies. My copy seems just dandy and that's comparing it with "El Supremo" the Nikkor 70-200 FL.

But then I shoot it at 7-30' and seldom at 200mm. For 200/280mm I use my EF 200mm F2.0 and a 1.4X TC.



Oct 01, 2017 at 04:15 PM
stflbn
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p.1 #9 · p.1 #9 · 70-200GM; Please help me reach a verdict


Looks to me like your camera is also not directly over the target... centered over the right side, which would make the left side prone to less sharpness under close scrutiny.


Oct 01, 2017 at 05:59 PM
stevesanacore
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p.1 #10 · p.1 #10 · 70-200GM; Please help me reach a verdict


Just my two cents but I've had three of those cheap plastic levels and they all were not accurate at all. Otherwise it should be easy to see if it's flat by making sure the perspective is perfect on the chart. You may also want to use the electronic shutter to take out any shake.


Oct 01, 2017 at 06:29 PM
 

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Mark_EL
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p.1 #11 · p.1 #11 · 70-200GM; Please help me reach a verdict


stflbn wrote:
Looks to me like your camera is also not directly over the target... centered over the right side, which would make the left side prone to less sharpness under close scrutiny.


Camera was directly over the target, just looks that way because of the wide angle of the iPhone lens which I shot the setup with...

stevesanacore wrote:
Just my two cents but I've had three of those cheap plastic levels and they all were not accurate at all. Otherwise it should be easy to see if it's flat by making sure the perspective is perfect on the chart. You may also want to use the electronic shutter to take out any shake.


I am aware of the lack of accuracy of my cheap spirit level. I've tested mine against a professional grade spirit level when I bought it and I know for a fact that one of the 3 axis is fine. So thats the only one of the bubbles that I actually look at ;-)

To give some background info of why I did this test, I took a few testshots in the shop where I bought the lens. In these shots I thought I saw some difference in sharpness between the left and the right side of the image. One of these shots was taken on a tripod, but in bad light etc. (@200mm, f2.8) Unfortunately this copy was the only one in stock when I was there, so I could not compare it to another copy. In the end I decided to buy this copy but made the agreement with the seller that I would do some better tests at home to see if it is defective or not.

Here is another shot I took, this time I had my camera (my A7II this time) mounted on the studio stand, pointing to the wall. .This is the same shot, but now with the camera put upside down.

After doing my tests, I am pretty sure there is a visible difference between the left and the right side. Now I do realise that I will probably never notice this in real life circumstances, as I've not bought this lens to shoot flat test chards ;-) But still, for a 3000 euro lens, should it not be fair to ask for a more even sharpness across the frame?



Oct 01, 2017 at 09:00 PM
Mark_EL
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p.1 #12 · p.1 #12 · 70-200GM; Please help me reach a verdict


Alright I want to bug you one more time, please bear with me

I took one more testshot, with a couple of flyers stuck against my studio wall and tried to set my camera as perpendicular to the wall as I could. I took two shots @ 200mm f2.8, one normal and one upside down. I've compared the same flyer side by side in Lightroom (the one with the sticker stuck on it), so the left is the normal shot, the right is the upside down shot.

This is the testshot I took:







This is the side by side comparison







Now, to me this looks like quite a big difference in sharpness. Could it give me issues IRLC I don't know?! (I shoot wide open quite a lot) But should I accept this or should I take it up with the seller to get it exchanged?



Oct 02, 2017 at 10:27 AM
Mark_EL
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p.1 #13 · p.1 #13 · 70-200GM; Please help me reach a verdict


Anyone? Is this something to worry about or would this be considered "in spec"?

Unfortunately I've hardly had any time to do a normal shoot with this lens. I did take some (wide open) portraits at around 120mm / 135mm yesterday which are incredibly sharp (can't show them online though) So thats a good thing. But still... I keep being paranoid, returning to these tests since this lens costs a boat load of money Just need to figure out if I should try to exchange this copy or not...



Oct 02, 2017 at 10:01 PM
Mystik
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p.1 #14 · p.1 #14 · 70-200GM; Please help me reach a verdict




Mark_EL wrote:
Alright I want to bug you one more time, please bear with me

I took one more testshot, with a couple of flyers stuck against my studio wall and tried to set my camera as perpendicular to the wall as I could. I took two shots @ 200mm f2.8, one normal and one upside down. I've compared the same flyer side by side in Lightroom (the one with the sticker stuck on it), so the left is the normal shot, the right is the upside down shot.

This is the testshot I took:

https://c1.staticflickr.com/5/4404/36740126764_c134067c16_c.jpg

This is the side by side comparison

https://c1.staticflickr.com/5/4506/23597447608_a362f692ca_h.jpg

Now,
...Show more

The first image is not perfectly perpendicular to the wall....you can tell by the tilt in the text.

Either way I'd go out and so some real shooting. If there are no issues shooting this stuff the way you would for real, then the lens is good. I've been very happy with mine.



Oct 02, 2017 at 10:46 PM
InFocus2014
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p.1 #15 · p.1 #15 · 70-200GM; Please help me reach a verdict


Mark_EL wrote:
Anyone? Is this something to worry about or would this be considered "in spec"?

Unfortunately I've hardly had any time to do a normal shoot with this lens. I did take some (wide open) portraits at around 120mm / 135mm yesterday which are incredibly sharp (can't show them online though) So thats a good thing. But still... I keep being paranoid, returning to these tests since this lens costs a boat load of money Just need to figure out if I should try to exchange this copy or not...



I do a lot of lens testing and have found that acquiring perfect focus on flat charts is a tall order (even with magnified view), so I now shoot detailed 3-dimensional objects, so I can see the precise focus point for tests other than the "brick wall" test. Of course, focus-by-wire lenses do not help. I constantly read accounts from "professional" testers where they found they needed to go back and re-shoot their tests because the focus was off. As an example, DPReview's current "Studio" setup shows somewhat blurry images from the A7RII, which is obviously a mis-focus (or a really bad lens).



Oct 02, 2017 at 10:56 PM
sungphoto
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p.1 #16 · p.1 #16 · 70-200GM; Please help me reach a verdict


I'd say the test image looks fine to me. Unless someone's paying you to take photos of test charts, it sounds like the lens is more than sharp enough to take pictures of people.

I personally didn't have any issues with my copy of the GM 70-200 f2.8. I found it to be as sharp as my Canon L 70-200 f2.8 II.

I'd stop obsessing over absolute sharpness and go out and shoot with it - there's more that goes into a sharp lens than just pure optical performance.



Oct 03, 2017 at 12:48 AM
Mark_EL
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p.1 #17 · p.1 #17 · 70-200GM; Please help me reach a verdict


Mystik wrote:
The first image is not perfectly perpendicular to the wall....you can tell by the tilt in the text.

Either way I'd go out and so some real shooting. If there are no issues shooting this stuff the way you would for real, then the lens is good. I've been very happy with mine.


Im not sure what you mean about not being perpendicular to the wall? It was straight on, pretty sure of it ;-)

Its been a few days and I've gone out in the street where I live to do a couple of testshots. I've also took some (test) portraits of my daughter in my garden, outside at 200mm and f2.8 in natural light. Shot @ 1/500 sec and ISO 125. I accidentally turned off IS, however @ 1/500 that did not give any issues of course.

This is one of the portrait shots that I took, using Eye-AF:







This is a 100% crop (SOOC, only converted from RAW to JPG)







This looks reasonable sharp to me, considering that we're talking about a 42MP file here. Still.. With every test I did, it's the same part (on the left) of the image thats just that bit softer. And perfectly perpendicular or not, its pretty obvious that if I turn the camera upside down that its the same part of the lens that is softer. (now shown on the right side)

Now of course the question remains, would this effect me in any way in real life circumstances. I don't know. I most definitely did not buy this lens to shoot flat test charts. But on the other hand, I am a bit worried that it would perhaps be visible if I use this lens to shoot group formals (which I usually do with a 70-200 lens). But if I decide to take it up with the seller and get it exchanged, could another copy perhaps be worse



Oct 05, 2017 at 12:31 PM
Mystik
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p.1 #18 · p.1 #18 · 70-200GM; Please help me reach a verdict




Mark_EL wrote:
Im not sure what you mean about not being perpendicular to the wall? It was straight on, pretty sure of it ;-)

Its been a few days and I've gone out in the street where I live to do a couple of testshots. I've also took some (test) portraits of my daughter in my garden, outside at 200mm and f2.8 in natural light. Shot @ 1/500 sec and ISO 125. I accidentally turned off IS, however @ 1/500 that did not give any issues of course.

This is one of the portrait shots that I took, using Eye-AF:

https://c1.staticflickr.com/5/4443/36841615033_c823e1c4a7_b.jpg

This is a
...Show more

The text in the first image is tilted and gets smaller from left to right...indicating that you are off axis.

Image of your daughter looks good to me!



Oct 05, 2017 at 12:35 PM
Mark_EL
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p.1 #19 · p.1 #19 · 70-200GM; Please help me reach a verdict


Mystik wrote:
The text in the first image is tilted and gets smaller from left to right...indicating that you are off axis.

Image of your daughter looks good to me!


In all honesty... i don't see what you see? But still, even if it was off axis just that tiny bit, I don't think that would explain the difference in sharpness with the lens turned upside down, no?



Oct 05, 2017 at 12:53 PM
AGeoJO
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p.1 #20 · p.1 #20 · 70-200GM; Please help me reach a verdict


Mark_EL wrote:
This looks reasonable sharp to me, considering that we're talking about a 42MP file here. Still.. With every test I did, it's the same part (on the left) of the image thats just that bit softer. And perfectly perpendicular or not, its pretty obvious that if I turn the camera upside down that its the same part of the lens that is softer. (now shown on the right side)


The depth-of-field at 200mm and f/2.8 is fairly shallow. What you described as slight softness may be related to that phenomenon.



Mark_EL wrote:
Now of course the question remains, would this effect me in any way in real life circumstances. I don't know. I most definitely did not buy this lens to shoot flat test charts. But on the other hand, I am a bit worried that it would perhaps be visible if I use this lens to shoot group formals (which I usually do with a 70-200 lens). But if I decide to take it up with the seller and get it exchanged, could another copy perhaps be worse

Group, as in several people? Either use a shorter focal length and since it is a zoom lens, zoom out to the shorter end. Or stop down the lens to increase the depth-of-field. You don't have to use f/2.8 all the time. And, most of all, stop worrying and put that lens to good use.



Oct 05, 2017 at 01:07 PM
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