21mm SEM on SL

[dsedov]

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I've noticed that the picture quality with the 21mm SEM is a little blurry than what I had on the M. Does anyone else experience similar problems on the SL with this lens? Closing aperture didn't help much for some reason. 

[Guest]

Nope I have not noticed this and this lens is the one I use more than any other currently apart from the 50mm and 90mm and sometimes the 135mm. The 21 is a great lens, I suggest yours is need of checking.

[eprom]

Yes, I feel the same - it´s a little bit blurry. The picture is not that sharp as on the M240. I had the same with my other M-lenses 35 and 50 Summilux, both where way better on the M. That´s why I sold all my M-lenses and bought the SL-Elmar Vario and that lens is top notch!

[Mikewest]

Very sad story ! I wanted to buy this lens with the SL...

So which wide angle do you recommand with the SL ? Is the 18 MM better ?

Thank you very much

[orc999]

no problem with mine, asph 3.4. perfert sharp and great lens.

Digloyd writes about some of them having a loose rear element causing blur, that would also show on the M though.(whicht btw I not have one to compare.)

[John Z. Goriup]

Sorry to be so blunt.........but this reeks of BS and nonsense.

 

You haven't told us anything about which adapters you use, how & whether you have set up your SLs for manual focusing, and if you feel that you can actually see when you're in focus on your SL.

 

I use the 21mm frequently, in fact it has become my favorite 'go-to' landscape lens, and the SL / 21 SEM combo consistently produces excellent, perfectly sharp images with without displaying the slightest problems, in fact, the SL / 21 SEM images are as sharp if not more so than with the 24-90 Vario Elmarit, which in my opinion is very sharp. 

 

In short, and again, forgive my bluntness, but believe me, if you're not getting images at least equal in sharpness to the best images those lenses delivered with your M body........it's you, not the lens !!

 

Permit me to raise another point: the 21 SEM has great depth of field, so if the images itb produces on the SL are 'blurry', it must be something else. Have you done any logical, methodical testing to try to narrow the problem down to a specific component / area, i.e. lens, camera, adapter, methodology.........etc ?

 

I submit it's much too easy to arbitrarily blame the lens without sufficient evidence to reach a conclusion, nor thinking this through and examining every aspect rationally and objectively.

 

Respectfully,

 

JZG

[dsedov]

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I'm using Leica M-Adapter-T  

I just shot a test, and I think the problem is always in the top left corner than anywhere else. I've also use focus peaking and scrolled all the way to that corner, but I can't get it to focus at all.

 

I've attached various crops to illustrate my point. 

 

@John - of course, I tried to understand the cause of the problem. I don't have my M, as I sold it to fund the SL, but I still have pictures I can look at and it looks like the lens worked just fine there. Other lenses I have (50mm lux, 90 elmarit) work just fine with the adapter. Even stacking another M-R adapter and using 60mm Macro I have produced great results. 50lux with open aperture has sharp focus across the frame as well. So it must be some weird combination of the lens and the camera. Maybe something happened with the lens between my last use on the M and first use on the SL.

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[dsedov]

Another thing I've noticed on some other pictures is that the blur appears to be directional (from the center) If I have a straight line that goes from the center of the frame to the corner it will be perfectly in focus. While surfaces that are perpendicular to that line blur towards the edges (especially toward the top left corner)

[chris_tribble]

Sounds like it might be a lens issue. As with others the SEM 21 is a go to lens on the SL for me and has given stunningly sharp results. One comment, I'd strongly recommend not using focus peak, especially with wide lenses. I had an embarrassing experience with the 28 cron asph where I had this turned on and produced a batch of soft images, something I've never done using unaided focus or magnification.

Good luck!

[dsedov]

Sounds like it might be a lens issue. As with others the SEM 21 is a go to lens on the SL for me and has given stunningly sharp results. One comment, I'd strongly recommend not using focus peak, especially with wide lenses. I had an embarrassing experience with the 28 cron asph where I had this turned on and produced a batch of soft images, something I've never done using unaided focus or magnification.

Good luck!

I have a feeling that that might be the lens as well. What's wrong with focus peaking though?

[LocalHero1953]

Depth of field is so large in wideangles (at most distances except very close) that focus peaking cannot identify the exact focus point. I find it's easier by eye.

[eprom]

I work as a pro for nearly 30 years and I know how to rate a lens on a camera. The SEM 21 is a stellar performer on the M240 and it is still beyond a lot competitors on the SL. But, all my M-lenses are better on the M240 than they are on the SL. They are still very good on the SL but the output with the M240 is better. It gets visible when you zoom in to 100% I´m not a pixel-peeper (maybe a little bit) and saw a difference and an overall look that I didn´t like that much - yes, you can call it blurry. It´s not bad the 35 and 50 Lux, they are ok but not 100%.

You see what´s possible when you compare it with the SL-Vario-Elmarit. 

 

Best,

Peter__

[chris_tribble]

I have a feeling that that might be the lens as well. What's wrong with focus peaking though?

Read Jono Slack's comments.  As focus peaking is only looking for contrast, in lots of scenes, especially with wide angle lenses, I've found that it can be very misleading and will show items as in focus when (especially if you're wide open) they're not.

[thighslapper]

I've noticed that the picture quality with the 21mm SEM is a little blurry than what I had on the M. Does anyone else experience similar problems on the SL with this lens? Closing aperture didn't help much for some reason. 

 

1. The poor performance of M w/a lenses on the SL is exaggerated by using them at close distances ....... you get the additive effect of field curvature (always present to some extent) and some corner smearing (not completely eliminated by the SL sensor microlenses).  It will also exaggerate any slight misalignment of lens elements ......or the camera being not perfectly perpendicular, so the effect may be more obvious in one corner. Worse also wide open. 

 

2. You need to focus infinity rather than using the stop on the lens ...... as the T-M (L-M) adapter is deliberately made approx 0.09mm too short to allow for leeway in lens calibration ..... and even with a w/a lens and considerable DOF you may still find distance OOF unless you set it manually.

 

3. Focus peaking is hopeless on w/a lenses and unnecessary ...... if it looks ok (even unmagnified) you are probably ok.

 

4. If the lens was faulty the issues would be easily visible on the M as well.

 

5. If you have a dodgy T-M adapter where it is not parallel to the SL sensor then issues will be apparent with other lenses as well.

 

Some logical investigation should reveal what is going on..... 

 

ps. I checked the 21/3.4 here and found SL and M performance about the same .....http://www.l-camera-forum.com/topic/252842-m-lens-performance-on-the-sl/page-6?do=findComment&comment=2929734

[eprom]

It´s not a question of "in focus or not" - it´s a bit blurry in 100% magnification. Don´t get me wrong, that´s kind of a luxury problem and can only be seen when you what´s possible with that lens.

[dsedov]

First of all, I'm sorry for the confusion. I don't spend a lot of time on forums or with other photographers, or reading manuals (for that matter). I confused focus peaking (which I don't use) with magnification (when you press the joystick on the SL), which I do use. So to rephrase my problem: I can't focus with magnification in the top and bottom left corner no matter what I do. I blame this on the lens, and partially on the sensor. It's definitely not the adapter, as all of my other lenses work great. Even if it was the adapter - it would mean that the focal plane is not parallel to the sensor, but it would not mean that there is anything I can physically do to focus that part of the image. I've literally explored the whole range from 0,7m to inf in attempts to find the focal point for that region of the frame - with no luck. Hense, the adapter is out of the question. I would doubt that there is something wrong with the sensor either, but I will need to investigate (currently looking into another 21mm or WATE). If all fails - the lens would be to blame.  

[adamdewilde]

Same with my (now sold) 21SEM. Worked perfectly on the M, and was very underwhelming on the SL. It was not as blurry as yours, but it was not sharp like on the M and the colors didn't have that POP like they did on the M. 

But ppl on here seem to want to defend Leica at all costs. So whatever good luck!

[hmathias]

1. The poor performance of M w/a lenses on the SL is exaggerated by using them at close distances ....... you get the additive effect of field curvature (always present to some extent) and some corner smearing (not completely eliminated by the SL sensor microlenses).  It will also exaggerate any slight misalignment of lens elements ......or the camera being not perfectly perpendicular, so the effect may be more obvious in one corner. Worse also wide open. 

 

2. You need to focus infinity rather than using the stop on the lens ...... as the T-M (L-M) adapter is deliberately made approx 0.09mm too short to allow for leeway in lens calibration ..... and even with a w/a lens and considerable DOF you may still find distance OOF unless you set it manually.

 

3. Focus peaking is hopeless on w/a lenses and unnecessary ...... if it looks ok (even unmagnified) you are probably ok.

 

4. If the lens was faulty the issues would be easily visible on the M as well.

 

5. If you have a dodgy T-M adapter where it is not parallel to the SL sensor then issues will be apparent with other lenses as well.

 

Some logical investigation should reveal what is going on..... 

 

ps. I checked the 21/3.4 here and found SL and M performance about the same .....http://www.l-camera-forum.com/topic/252842-m-lens-performance-on-the-sl/page-6?do=findComment&comment=2929734

 

All excellent and well thought-out points, but a out of parallel M-Adapter T is unlikely, but still possible. Any wide angle lens has a great depth of field but a short depth of focus (the distance tolerances of good focus at the image plane). The more extreme the WA lens the poorer the depth of focus. That is also worsened by curvature of field, which all WA lenses have. Those are the main reasons why ultra-wide lenses rarely have wide maximum apertures. 

 

The lens mount flange alignment is always very critical on ultra-wide lenses. Their mounts must be strictly orthogonal to the focal plane to hold focus at all. 

 

Harry

[HeinzX]

The M lenses are not telecentric - in principle they were constructec for film and the Ms. To overcome this problem, Leica has constructed the digital lenses with microlenses on the chip. Same has been doneon the chip of the SL to make M lenses usable. But imho not all do perform as good as on the Ms.

I have sold my 18 mm SEM and use for ultra wide angles the Canon 11/24 together with the Novoflex

adapter on the SL - and this works very well. Disadvantage is, that this is a very bulky lens, but that

is the case with the Leica 24/90 too. Pricewise it is not a cheap lens, but worth the money. Price of

this lens is slightly below Euro 3000 - the Novoflex adapter costs somewhat below Euro 500 but can also be used for other lenses of Canon i.e. for the excellent TS- 17 mm, which could be of great interest

for those, who need an ultra wide lens with tilt/shift correction possibility.

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[Guest]

Sorry to be so blunt.........but this reeks of BS and nonsense.

 

You haven't told us anything about which adapters you use, how & whether you have set up your SLs for manual focusing, and if you feel that you can actually see when you're in focus on your SL.

 

I use the 21mm frequently, in fact it has become my favorite 'go-to' landscape lens, and the SL / 21 SEM combo consistently produces excellent, perfectly sharp images with without displaying the slightest problems, in fact, the SL / 21 SEM images are as sharp if not more so than with the 24-90 Vario Elmarit, which in my opinion is very sharp. 

 

In short, and again, forgive my bluntness, but believe me, if you're not getting images at least equal in sharpness to the best images those lenses delivered with your M body........it's you, not the lens !!

 

Permit me to raise another point: the 21 SEM has great depth of field, so if the images itb produces on the SL are 'blurry', it must be something else. Have you done any logical, methodical testing to try to narrow the problem down to a specific component / area, i.e. lens, camera, adapter, methodology.........etc ?

 

I submit it's much too easy to arbitrarily blame the lens without sufficient evidence to reach a conclusion, nor thinking this through and examining every aspect rationally and objectively.

 

Respectfully,

 

JZG

 

I suspect a faulty lens myself. My 21 SEM plays wonderfully with the Adapter-T and I just get wonderful results. No problems with M lenses and the SL. So by the sound of it, I must be lucky.