Thanks Nomad.

Tbh you are pretty much distant enough at that i'd of thought. But perhaps the further you go the more noticeable it is. I'd appreciate it if you could upload some full res pics, though it is a real pain to keep track of what you're doing with no aperture in the EXIF. So you would say that fully zoomed in with the focus assist the subject is focussed (perhaps not quite as sharp, its at the edge of the lens after all) at the edge with the same focus setting as you had with central focussing. Centrally focussed seems to be pretty much on the money for the infinity lens marking for me. Edge focus achieved by going to the rotation stop of the lens past infinity.

I've just had a quick go with the pen, and the issue is much less noticeable.. i'm just looking at the images i got now. I think the main thing though is the resolution difference may make the anomaly harder to see.

@nomad - eek. If it's not normal i'm going to be pretty miffed. 2 lenses, i thought would imply that its pretty much just a feature of the lens.

I don't think a large evaluation chart will let you test anything other than curvature up close.

Did you try with the steps i outlined in my earlier post, just using live view and something 100m+ away, as close to actual infinity as possible... focussed centrally, out at the edges and fixed by focussing beyond infinity.

You're making me question whether or not my GH2 could contribute. I have access to an olympus pen, i'll see if can try the same test on that to see if it has the same results.

I'm also going to email Voigtlander directly. They should be able to say one way or the other whether this is "normal" for this lens. If not, i'll presume they could perhaps exchange it and test the replacement, or perform a fix. whatever. And get one that was much better or perfect.

Thanks for trying Nomad, look forward to hearing any more results. Would ask that if you've not tried something v distant as outlined before that you could try.. the key is infinity... I don't know how far away a roof opposite your house is :) Use my shots as reference for what i'm talking about for real distant focussed subjects.

Cheers

http://www.flickr.com/photos/jimbobuk/7658911146/in/set-72157630781100484

This shot I think shows the curvature of sharpness quite clearly. The centre in focus trees are fairly distant, the hedge top and fence is perpendicular and square to the lens. It is soft at the centre, sharp at the right edge, and even the top of the building on the right has some sharpness on its roof, even though this is really quite close to me.

I've written more notes in the image description, but the amount of curvature on this "plane" of focus is rather extreme, I almost imagine visualising it like looking into a bowl, with perhaps quite steep walls.

Dofmaster shows that lens at f1 on the gh2 is hyper focal at 20m, with sharpness from 10m to infinity. To get this degree of unfocusedness at the corner would need to have some serious curvature or other defect to overcome such a large wedge of what should be focused.

Anyways, hopefully they're all the same in this respect, and let's face it we will be shooting 98% of stuff wide open and in that sweet spot of 0.5m to 2m where the shallow DOF is most noticeable and causes the subject to pop out of the scene in such a nice 3d way!!

@bheath, thanks for trying to see if your copy is similar. Tbh at this price there shouldn't be much variation in performance I do think it's just a characteristic of the lens. Just be nice to know that say 4 or 5 lenses exhibit this issue at infinity to be sure. You're right that you need to know this and compensate for it, I think the issue means this is not a good lens for landscapes, and also means if you want a large amount in focus past 10m or so it pays you to stop down and judge your focus point very carefully. It's much easier to do the test live with the focus assist vs taking pics.

@ralph_b if you read my descriptions for each test shot then look at the full res versions you will understand that the buildings closer to me on the street are not the thing I'm focussing on. It is always the houses at the very top of the street furthest away that I'm looking at. These are 200m away perhaps more. I focus on them at the centre of frame take a shot, then I recompose the shot with that subject at the edge of the frame and take another shot. The distant houses are then out of focus. This doesn't happen with other lenses I own, including the 25mm.

I think it's depth of field is extremely curved, regardless of aperture. It's just as you stop down the increase in sharp DOF is able to start to compensate for this defect. It's still noticeable at f4, but much subtler.

@nomad, would be great to have your copy tested too. Would give me some peace of mind, and I think it's worth knowing about its limits. Not heard of this Rokkor VFC lens, nice to know it could manipulate such a phenomenon.

Just received the 17.5mm on Thursday and after some brief playing I gotta say 'wow'! Yes it is dreamy at F0.95 but my Pentax SMC-A 50mm F1.4 is at least as dreamy (maybe marginally more) wide open @ F1.4.

The Voigtlander tightens up substantially by F1.4 and at 1080 video resolution doesn't lack sharpness providing of course you nail focus.

Here's some ungraded frame captures from few rushed clips.

Er apologies for the subject matter but I sent the bikini clad babes out to get the beer and pizza and by the time they'd returned my battery was out of juice ;>)

All shot handheld (no rig) with Cluster v6 'DREWnet' @ ISO160, Smooth -2,-2, 0, -2, 1/50th between F1.4 & F2.0.

Lighting was a mixture of factory ceiling hung fluros and skylights.

I think I'm going to enjoy this lens it's just a pity I can't use it on my Pentax K5.

Okay I'll do exactly that. But I must say, when things get darker, and you are wide open, it's up to the photographer to compensate for lens abberations and lack of focus continutity. We're in a whole new realm with these .95 lenses, so we must adapt. I think this better glass than the cp ziess primes. The cooke cine lenses are much better, but I never shoot them under t3. These voightlander [almost cine] lenses are a godsend. Learn them. (as you are) I think their quality control is what makes them so good. Hope this helps. In my books its an inexpensive prime. But I dont want any "white spots" on it for Chris' sake.

@jimtreats it´s pretty normal for any lens to be softer out wide than in the centre.. even more so on a wide-ish lens, but like it says above, it can be slightly more curved (aimed towards centre sharpness) than "normal".

Ok. So my replacement lens has arrived and i've had chance to play with it a little..

I'll put a few snapshots up that i've taken whilst testing it when i can.

In short. It's still got quite a lot of the problem that the last one had. I now realise this is probably just how this lens is.

I would really appreciate it if you other guys who own it could just conduct this small test and tell me if you have similar issues.

• go somewhere where you can see something as far away as possible, 100s of meters away would be great!
• have the lens wide open, and use the GH2's focus assist on its most zoomed in setting (rotate the back wheel after clicking it to zoom in a little more than the default zoom amount).
• move the focus assist section to the centre of the frame and focus the lens at infinity. You'll find that the lens is pretty close to the infinity markings on the lens
• now move the focus assist to the far right or left of the frame and turn to frame the same subject you had focussed previously
• you should observe that it's not as nicely focussed as it could be. You can then rotate the lens past infinity and see that the distant element actually comes into more sharper focus
• if you then return the assist window to the centre with the lens in this focussed state you'll see the centre and most of rest of the frame is actually quite out of focus

It's as i described before, but perhaps slightly better than it was. I've been able to shoot in a little more light and also experiment with stopping down. Of course this lens isn't sharp wide open, and even less so at the edges. I don't think this is what i'm seeing though.

I believe the problem is a curved "plane" of sharpness. I'm going to do some googling to find a review that i'm sure I read that stated as much, that the focal plane isn't a plane at all. Due presumably to the incredibly wide open aperture and very wide lens construction.

I've got a nice photo focussed at about 10m or so, which nicely shows that the sharpness plane isn't flat.

When you start to think in terms of infinity you get what i'm seeing. Focus at infinity and this curvature means that the edges aren't actually in focus, closer to infinity is. Focus the lens past infinity and this curvature brings the edges into focus.

What i've been able to see with this lens that i THINK is better than the original one i had is that if i stop down and also err on focussing slightly past infinity i'm able to get a lot of the frame acceptably sharp.. This is all i really need to know.

I'll re-post when i've uploaded the new shots i've taken.

In the meantime I would really appreciate it if a few other owners of this lens could perform the test i outlined above and confirm that they too have this issue at infinity focus with the lens wide open, or not stopped down massively.

Cheers

I cancelled my order for the 12-35 f2.8 and ordered this one.

Window light indoors?

When I first started newspaper photography decades ago, my Nikkor 24mm lived on my camera.

That lens opens a new world of composition possibilities.

But the 17.5 shouldn't distort as much, and will, I think, be much better for common video applications.

RBD

Did I say I'm excited?

@bheath - thanks for the advice. I sent the lens back to the seller last week, they're going to exchange it for me and hopefully the next one will be a good copy.

Going through more and more of my footage from holiday taken with it, I can see the effect of the defect more and more. Still, some people would apply such an effect via instagram and the like :) Will see how it all turns out.

Cheers!

Sheesh-

Seb Farges has seduced me.

I saw his video, and I want this lens.

Hello?

Just because he can make this video with this lens, doesn't mean I can.

But the boy knows exactly what video is all about.

People, and movement.

I come from a journalistic background--features writer, photographer--so I don't have much time for the Zacuto shootout.

Who has people to light a scene for you?

Journalism is making the best of ambient--conditions at hand--lighting.

In Seb's video... the dancers are moving so fast I can't tell if the lens is sharp.

Still...

Seduced or not, I want this lens.

RBD

Hey everyone.

So a few weeks ago my 17.5mm lens arrived and I was very happy with it on initial examination.

I got my B&W UV protective filter on it as soon as it arrived and shot a few tests with it.

I've since used it at a friends wedding reception where it worked really well.

I then prepared to take it with me on my holidays to Paris. In doing last minute cleaning of my kit i noticed a scratch on the front element, it'd been covered since I'd had it with the filter, so I knew it was a manufacturing defect. I also expected that although it bugged me now i'd noticed it, it'd probably have practically zero effect on the actual images captured.

My holiday in Paris went well, for the first time my GH2 was hacked with Sanity and performed flawlessly, i've got to go through my footage and stitch together some amateurish stuff for fans of the lens and that hack.

On arriving back home I started just going through all the footage and stills I shot on the tv. I noticed something on some videos and then finally in some stills it became really pronounced. Basically areas of my frame were not in focus at infinity, namely the horizontal edges when in landscape.

I put some photos of the scratch and an example out of focus shot up here

http://www.flickr.com/photos/jimbobuk/sets/72157630609829882/with/7585971080/

It was hard to know with no exif recording whether its down to user error or not. I'd heard that the focal plane was curved slightly as well but I'm now convinced that there's something not right with the lens.

I also own it's brother the 25mm lens, and just now have confirmed that it doesn't suffer the same problems. Basically I went outside and used the maximum crop zoom on the camera to look at the centre zone, and the far right/left and try to nail focus on some houses that are about 300m away.

The 25mm focusses roughly at the infinity sign for all areas. The lens has always focussed beyond infinity on the barrel and when doing so the image is just unsharp.

The 17.5mm focusses roughly at the infinity sign for the centre of the image, but the left/right edges of the image are only focussed when the lens is rotated past infinity till it stops. At this point the centre of the image is no longer fully in focus. This phenomenon carries on past f4 so even increasing the DOF can't rescue it till we get up to f8 and diffraction is making it less sharp regardless. Also I was trying this at dusk so the sensitivity went so high that the resolution we are talking about just wasn't resolved anymore.

I think in the shot of the church in my flickr set you can see this phenomenon happening with the stained glass window, which as shot was at the right of the frame. Ok i'm not perfectly square but the far wall is about 50m away, and the top of the wall is perhaps another 30m away, i don't know. All i do know is that the detail is significantly sharper even with the small bollards that are only a few metres away from me. It seems its just an out of focus issue that cannot be resolved.

I'd appreciate it if anyone who owns this lens could test this on their copies and tell me whether or not they exhibit similar issues in and around infinity.

I contacted the seller before the holiday about the scratched front element, but i'm about to contact them again ready for return/exchange as i can't work with a lens so unsharp when trying to focus on relatively distant subjects.

Sorry for the long post!

Well, the deal is closer to 1.100 €, but still quite nice!