Defective Oly 25mm lens

Today I tested a new lens that I purchased from B&H Photo.  It is an Olympus 25mm f1.8 lens.  It was bought during the recent Olympus sale.  I had great expectations after having researched the lens.  Sadly it is a lemon.  The left side is blurry and the right side is sort of sharp.  I have trouble believing that such a defective lens was allowed to pass the Olympus "quality" control and was sold by a reputable company like B&H.  B&H has agreed to give me a full refund and even sent me a return shipping label.  I think their service is terrific and am not blaming them.

I wonder how many other lenses having this problem are out there with unsuspecting photographers?  For photographers wanting edge to edge sharpness, my experience shows the importance of being able to return a defective lens and of testing it before the return period is up.

Below is the full size image so those interested can zoom in and see what I mean.  It was taken at F4, which should be its sharpest stop.  I took many others and the results are the same, unsharp on the left and sharp on the right.  I took high res and regular res, but am posting this regular res because my internet connection can't handle sending the high res image.

I also took the scene with my Panasonic 14-45mm lens, and these images are normal edge to edge.  They are much sharper on the left edge than the Oly 25mm, but not quite as sharp as the Oly on the right edge.  Some of you may think I am being too particular.  But it makes no sense for me to buy a prime lens that is not as sharp as my zoom lens.

Taken with a defective Olympus 25mm lens, f4.  Unsharp on the left, sharp on the right.

What happens if you take a picture, then take it again with the camera upside down? If the problem swaps sides, I would say to return the lens.

Betarover wrote:

Today I tested a new lens that I purchased from B&H Photo. It is an Olympus 25mm f1.8 lens. It was bought during the recent Olympus sale. I had great expectations after having researched the lens. Sadly it is a lemon. The left side is blurry and the right side is sort of sharp. I have trouble believing that such a defective lens was allowed to pass the Olympus "quality" control and was sold by a reputable company like B&H. B&H has agreed to give me a full refund and even sent me a return shipping label. I think their service is terrific and am not blaming them.

I wonder how many other lenses having this problem are out there with unsuspecting photographers? For photographers wanting edge to edge sharpness, my experience shows the importance of being able to return a defective lens and of testing it before the return period is up.

Below is the full size image so those interested can zoom in and see what I mean. It was taken at F4, which should be its sharpest stop. I took many others and the results are the same, unsharp on the left and sharp on the right. I took high res and regular res, but am posting this regular res because my internet connection can't handle sending the high res image.

I also took the scene with my Panasonic 14-45mm lens, and these images are normal edge to edge. They are much sharper on the left edge than the Oly 25mm, but not quite as sharp as the Oly on the right edge. Some of you may think I am being too particular. But it makes no sense for me to buy a prime lens that is not as sharp as my zoom lens.

Looks similar to my 25/1.8 adventure.

I had three 25/1.8 lenses, one good sample in 2014 and two lemons in 2016:

• Early sample which was tack sharp, better than the 20/1.7 it replaced. Unfortunately I had to sell it but now I decided to buy a 25mm again ...
• I got a very bad sample, worse than yours but similar: the left 25% were blurry and only stopping down to f5.6 could help. I sent it back as obviously "defect"
• The replacement was much better but the left corners were still soft, not on par with the 20/1.7 or even the 25/1.8 I owned before. I gave up and returned the lens
  (I have the perfect 12-40 zoom and I don't need a fast prime which is soft)
• Finally, I bought a Panasonic 15/1.7. Again, soft left corners. I gave it to repair and they replaced the optics. Now, finally, the lens is how it should have been at the beginning...

I am a little bit disappointed, three lemons in a row. I bought and sold many lenses before and did not have any issue.

Buying lenses no longer is big fun for me, I am very careful now ...

Sadly but there exists no quality control procedure for this category of lenses that includes a test for decentering or "uneven sharpness". A lens will be subjected to a basic control to see that it "functions" but other than that there is only an occasional random sample that is tested to see whether the assembly like is still working properly or is out of whack.

And a vendor cannot do any quality control either as they don't want to touch an item they are selling as new (unopened).

So the reality is you play in a lottery when buying a lens. Even going through 5 bad copies can happen with almost every lens type from every manufacturer.

Paul De Bra wrote:

Sadly but there exists no quality control procedure for this category of lenses that includes a test for decentering or "uneven sharpness". A lens will be subjected to a basic control to see that it "functions" but other than that there is only an occasional random sample that is tested to see whether the assembly like is still working properly or is out of whack.

And a vendor cannot do any quality control either as they don't want to touch an item they are selling as new (unopened).

So the reality is you play in a lottery when buying a lens. Even going through 5 bad copies can happen with almost every lens type from every manufacturer.

What makes me nervous is the impression that while the cameras and sensors get better and better, the average quality of the lenses is getting worse (if you don't count the PRO lenses).

I did not have any issue with the older lenses I have or had. Other people seemed to be happy too. For example there are not many issues with the Panasonic 20/1.7 lens besides the pathetic AF. They really sold many but this forum did not fill with complaints.

But I see a lot of complaints with Olys new PZ kit lenses and the 25/1.8.

So after reading several threads about decentering on the Oly 25 mm f1.8 lens. I did a careful test with mine. Camera on tripod aimed at a sheet of typed text taped to a wall. Checked the images shot at F1.8, 2.8, 3.5 and 4.0. Don't see any sign of decentering.

Guess I got the only good copy from the batch. (bought mine last summer from B&H).

Dick

Betarover wrote:

Today I tested a new lens that I purchased from B&H Photo. It is an Olympus 25mm f1.8 lens. It was bought during the recent Olympus sale. I had great expectations after having researched the lens. Sadly it is a lemon. The left side is blurry and the right side is sort of sharp. I have trouble believing that such a defective lens was allowed to pass the Olympus "quality" control and was sold by a reputable company like B&H. B&H has agreed to give me a full refund and even sent me a return shipping label. I think their service is terrific and am not blaming them.

I wonder how many other lenses having this problem are out there with unsuspecting photographers? For photographers wanting edge to edge sharpness, my experience shows the importance of being able to return a defective lens and of testing it before the return period is up.

Below is the full size image so those interested can zoom in and see what I mean. It was taken at F4, which should be its sharpest stop. I took many others and the results are the same, unsharp on the left and sharp on the right. I took high res and regular res, but am posting this regular res because my internet connection can't handle sending the high res image.

I also took the scene with my Panasonic 14-45mm lens, and these images are normal edge to edge. They are much sharper on the left edge than the Oly 25mm, but not quite as sharp as the Oly on the right edge. Some of you may think I am being too particular. But it makes no sense for me to buy a prime lens that is not as sharp as my zoom lens.

Taken with a defective Olympus 25mm lens, f4. Unsharp on the left, sharp on the right.

I don't see a problem.  If you find subjects on the left and right that are roughly at the same distances, particularly near the distance of focus on the center, they look comparably sharp to me.  I think your expectations might be unrealistic for this lens!  It has never been regarded as one of the outstanding Olympus primes, nor is it priced as such.

IMO, that is NOT a good test case - depth of field is too deep.

Try something with a flat plane - a framed picture, a printed A4 paper, etc.  Shoot upright and upside-down as suggested by other posters.

That 14-45 sure is sharp on the left, but falls off on the right and the Oly is better there.

It is distressing that the quality of new lenses is so hit or miss,, but your 25mm isn't as bad as some others  I've seen.

MayaTlab0 wrote:

As Martian Flatcar suggested, I'd try to perform the upside down test first with this lens :

http://www.dpreview.com/forums/post/51037446

However, given that you are far from the only one who's noticed a front focusing left side on the Olympus 25mm f1.8, there are very good chances yours is a lemon (and some chances you'll have a hard time finding a decent one :

http://www.dpreview.com/forums/thread/3978582#forum-post-57435654

Yep, my 25mm was decentered (left side blurry) and my 45mm was also decentered (right side blurry). Seems to be common on both lenses. My 12-40 is flawless and has replaced both of my Oly primes (now sold). My only prime now is the 20mm which is also flawless optically, at half the price of the Oly primes.

Honestly, I find the Pana image soft on the _right_.  (Look at the small words in the "Legend Auto Sales" sign, for instance.) I'm sure you're trying to give comparable images, but I am wondering whether the focus point is the same in these two images?

I think the suggestion of taking a picture of a flat surface both right-side up and upside down is a good test even if it doesn't match your photo style, as it is a reproducible test of the lens and allows ruling out focus variation and camera concerns.

Betarover wrote:

Some here have suggested I test this lens by photographing a sheet of paper. I do landscapes and for me such a test may not be useful. Consider the geometry. If a sheet of paper is photographed, the edges, and especially the corners, would be at a slightly greater distance from the lens than the center. If the lens is engineered to compensate for this small difference in distance when it is focused near, has it been correctly engineered for a flat plane when focused on infinity? Are the elements within the lens engineered correctly so that they move relative to each other in a way that allows both near and distant images to be sharp, corner to corner? How can one be sure, except by photographing a distant landscape where all elements are so distant as to be considered at infinity?

Another posting feels I am expecting too much from this lens. Not so. The image below shows that my Panasonic 14-45mm zoom is much sharper on the left. Clearly the Oly 25mm is a defective lens, and I am "pleased" that others have posted here having had the same experience.

The intent of this thread is to alert others that there are bad lenses out there and if edge to edge sharpness is wanted, one should be afraid to buy from a source not giving a satisfaction guarantee.

The images below show the scene, edge to edge across the middle, for my Panasonic 14-45mm and the defective Olympus 25mm. Each was taken at their sharpest f stop, and both are taken in the Hi-Res mode.

Images taken with Oly EM5 Mk 2, Hi-Res mode.

Compare f/5.6!  Of course there is more DoF for the 14-45 case.  This test is also meaningless.  The left side detail is much closer than your focus point.  It is meaningless to compare sharpness for ANYTHING except at the focus distance.  If you want to compare, zoom in to the left edge and manually focus to optimal sharpness and then compare.  When looking at 100%, there is NO depth of field.  It is all out of focus except for exactly one distance, and that distance varies over the image surface.

I said you are expecting too much because the Olympus 25/1.8 is simply NOT a great lens.  Perhaps every now and then, somebody gets incredibly lucky with a great copy, but I doubt very much that your copy is out of spec.

It does not review well, and it isn't stellar.  That's why it is also cheap.  For that matter, Nikon and Canon 50mm f/1.8 lenses are designed to be cheap and aren't all that great, even in the new Nikon G version or the Mk II version from Canon.  They are OK, but they aren't pro lenses.

I picked up the Panasonic 25mm f/1.7 @$99 (two copies, actually), and they are both OK.  Not great; not terrible, but OK.  For the price, I'm happy.  I wasn't expecting a pro lens.  Don't confuse this lens with the Olympus 45/1.8, 12/2, 75/1.8, etc.  It is not in the same league (as is the case for the 17/1.8).

The 'right' way to test a de-centered lens is to shoot a flat scene like a piece of printed paper. And you've a controlled environment which should be invariant to aperture values. In theory, you should be able to test it from f1.8 to f22.

Your point about shooting landscape is valid in everyday use cases but not for testing de-centering. What conclusion can you draw if a shot looks perfect at f22 but not at f8, say?

Edit: the new pic with the 25mm looks fine to me(left hand is not any blur-er than right) and much better than the zoom.  IMO.