Is this the expected corner performance of Olympus M.Zuiko ED 75-300mm f4.8-6.7 II ?

I just received Olympus M.Zuiko ED 75-300mm f4.8-6.7 II lens, refurbished, directly from Olympus USA.  I got it for a great price thanks to the recent spring sale, but I'm beginning to think that there may have been a reason why it was refurbished in the first place.

Top-left corner from a shot at 75mm, wide open.  This is not even the worst corner.

This was shot under controlled conditions (tripod, MF, IS off, anti-shock).  It's actually very good in the center, but corners are pretty soft, and they don't sharpen up until f/11 (and even then, only just).  Online reviews indicate that the lens should be tack-sharp corner-to-corner at this focal length, even wide open.  Did I get a bad copy of the lens?

I'm thinking of returning it, but I thought I would check first with others who have experience with this lens.

For reference, this is the full version of the above shot.

A couple of things:

- How close is this - many lenses don't perform as well when at close distances

- How do you know that you had the lens optical axis perfectly perpendicular to the test target?

- Field curvature - did you test with the focus optimized for the center only or did you try adjusting the focus so that the corners where at best focus?

Hello,

I did very similar test shots for all of my lenses, all in all about 12 lenses.

The behavior is as expected and is "middle class". There are lenses much worse (take the PL25/1.4 at aperture 1.4 with this target ...) while others are near to perfection (Oly FT 35/3.5 Macro, Oly mFT 75/1.8 or the PL25/1.4 at f5.6).

For a 300mm lens your result is not this bad and sending it to Oly will be quite useless.

Take a look at my Panasonic 12-35mm tests, while the focal length is completely another story the corner crops are similar to yours (take into account that you did not align the corners, so your pictures are smaller and are expected to show more blur)

http://www.dpreview.com/forums/thread/3383965

You can also compare your impression with the measurments at slrgear.com .

P.S.:

I have test shots for my ex 75-300 Mk1 as well as my 75-300 Mk2. If you want and if I have access to my home-PC I can forward these test photos to you. If you want, send a message to trigger me ...

Saw your PM.

Regarding the slrgear test chart: I was not aware that you were testing the short end at 75mm.

The short end is a complicated story:

I had both versions of the lens: Mk1 and Mk2. As far as I remember the Mk2 version was optimized for the medium to long end, meaning that resolution and corner sharpness was best from 100 to 220mm. Which is good in my opinion (wished they would have optimized it for 300mm)!

The older mk1 version (at least my sample) was optimized for the short end 75 to 140mm, but if I buy a super tele, I am interested in the long end, not the short. Therefore I found Mk1 a little but annoying ...

As slrgear never tested the newer mk2, the chart above is not applicable your your case, unfortunately. Indeed the newer lens was a little bit soft at the short end as far as I remember.

I will try to find the corresponding test photos from my lenses later ...

CrisPhoto wrote:

Saw your PM.

Regarding the slrgear test chart: I was not aware that you were testing the short end at 75mm.

The short end is a complicated story:

I had both versions of the lens: Mk1 and Mk2. As far as I remember the Mk2 version was optimized for the medium to long end, meaning that resolution and corner sharpness was best from 100 to 220mm. Which is good in my opinion (wished they would have optimized it for 300mm)!

The older mk1 version (at least my sample) was optimized for the short end 75 to 140mm, but if I buy a super tele, I am interested in the long end, not the short. Therefore I found Mk1 a little but annoying ...

Hi Cris,

Note that the Mk1 and Mk2 versions of this lens are optically identical (save for the lens coatings which are new on Mk2). So what you saw were sample variations rather than design differences.

Also, I am not sure I share your judgment that the lens of the OP is healthy. Have a look at SLR Gear's test shot here (their so-called VFA target) at 75 mm wide open and compare with that of the OP.

http://www.slrgear.com/reviews/zsamples/olympus75-300f48-67m/zolympus75-300f48-67vfa075f48_ep1.jpg

As slrgear never tested the newer mk2, the chart above is not applicable your your case, unfortunately. Indeed the newer lens was a little bit soft at the short end as far as I remember.

I will try to find the corresponding test photos from my lenses later ...

-- hide signature --

OM-D + Sam7.5, PL25, O60, O75
P12-35, O75-300

Hi Anders,

Olympus itself says that the second lens has one ED element less. And me as well several others say that the new lens is sharper at the long end. But you are right, our observation could be sample variance. But only someone like Roger from lensrentals has enough lenses to rule out sample variation.

And for Kamil,

Here are the crops I promised earlier, full samples are on the way via email. If you compare them, for 100% comparability please assure you have

• a target at A2 size (may consist of 4 sheets A4)
• used a 300 or better a 600dpi printer (in your test I see heavy pixel artifacts in center and even in the edges)
• the edges of your test shot are aligned to the 4:3 markings +5mm
• used flash to rule out motion blur

Here are my 4 edge crops which are only roughly comparable because your edges are not at 4:3 mark. But I would say your lens looks not very different.

I know, shooting stupid test charts is not as easy as one might think. And am for sure not a good expert. But your test pic quality has to be improved, see your and my center crop. If the center is similar in sharpness, we can start talking about the edges.

CrisPhoto wrote:

Hi Anders,

Olympus itself says that the second lens has one ED element less. And me as well several others say that the new lens is sharper at the long end. But you are right, our observation could be sample variance. But only someone like Roger from lensrentals has enough lenses to rule out sample variation.

Where to they say that the second version has one ED element less? Here are the lens designs as presented by Oly themselves and they are identical as far as I can see: 18 elements in 13 groups, one super ED element, two ED elements, three HR elements. The manufacturer MTF charts are identical as well.

http://asia.olympus-imaging.com/products/dslr/mlenses/75-300_48-67/

http://asia.olympus-imaging.com/products/dslr/mlenses/75-300_48-67ii/

Unless Oly provides false information about the optical design of the two versions, that leaves sample variation as the only possibility. Besides, if they had taken away an ED element in the new version, that would lead us to expect worse rather than better performance from that version.

Milek,

glad to see that your are trusting the lens now. Don't want to stir you up but if you want to test the weak corner you could turn the camera 180° if you can mange this. But I would not know how to do it precisely enough without lens collar....

Yes, I confirm, printing test charts is nearly as complicated as shooting them.

The pixel artifacts in my charts make me assume that the printer, while in 600dpi mode, actually printed in 300dpi resolution. Maybe it is the dark grey tone (for MTF measurements, the chart has to be grey, because otherwise you would clip sharpening artifacts).

But maybe for our purpose and printers, a b/w version would be better

Have fun with you lens, I really enjoyed the 300mm range, but because of the bad light in winter , I have switched to 50-200mm currently ...

Christof

This is (a crop) the corner performance of my copy at 300mm handheld f/6,7 iso800.

I bought this lens a week ago (March 2023) and a distant shot at f/8 is extremely sharp corner to corner. I have not checked other settings but casual shots suggest similar until at least 200mm.