Biogon 25mm f2.8.... Anyone using it on Xpro1?

[f16sunshine]

I'm on a job where I'm stitching Panos and the xpro1 has been great but....
I would like to have a wider lens to cut down on the number of frames for some scenes.
I've owned the ZM 25mm before and it was wicked sharp and resolves like a mother on the M8!
Does it work well on the xpro1? Does it smear edges and corners like some other wides seem to?
Anyone have any experience to parlay? Thanks in advance!

[Shutterspark]

No personal experience, but when researching the same thing myself I did come across this:

http://www.flickr.com/groups/zeissik...7630553445286/

Doesn't look very promising.

[irq506]

yes id be veriy curious to see anything anyone had on this combination.

[bobbywise]

Originally Posted by Shutterspark

No personal experience, but when researching the same thing myself I did come across this:

http://www.flickr.com/groups/zeissik...7630553445286/

Doesn't look very promising.

Ah, that's real bogus. I was about to get this lens with the m adaptor. Oh well, I'll just stick with my Minolta Rokkor 24mm and kipon adaptor until Fuji bring out the native lens at 35 mm ff equiv. thanks for this link

[semilog]

It'd be extremely helpful if people would actually show examples. Preferably, direct scene-for-scene comparisons to the M8 and/or M9.

[semilog]

Originally Posted by rbelyell

i would love to see more results.

I would love to see any results with this combination, provided that they are carefully acquired.

[deleted; the links I'd given were to images taken with the ZK Distagon!]

[pieter]

Originally Posted by semilog

I would love to see any results with this combination, provided that they are carefully acquired.

Ah. Here we go. That wasn't difficult.

Sharp enough that it's exciting aliasing near the edges of the frame -- and that on a sensor on which it's difficult (though not impossible) to get aliasing. Here's another good example.

That'll do nicely, I think.

Just make sure you don't confuse the Zeiss 25mm ZK Distagon and the Zeiss 25mm ZM Biogon.

[semilog]

Ooooh. I blew it!

That ZK Distagon sure looks good, though!

:-/

Many thanks to Pieter for catching my error so swiftly.

[BobYIL]

Originally Posted by semilog

It'd be extremely helpful if people would actually show examples. Preferably, direct scene-for-scene comparisons to the M8 and/or M9.

Note that the XP1 sensor employs no offset microlenses to handle oblique rays properly and being APS-C format do not expect flawless performance from it with the conventional wide angle lenses; hardly any different than the performance of the Nex-7.

Here you will find a variety of lenses (some top ones too like the Leica Asphericals and the Biogon 21) performing on the XP1. They all smear through corners, they all show a ton of CA through edges except the ones designed specifically for the XP1 sensor, i.e. the native lenses.

http://picabroad.com/2012/03/24/fuji...-mount-lenses/


I think the APS-C format mirrorless cameras with offset microlenses like the Ricoh GXR or the Nex-5N can deliver satisfactory results with the RF wide angles. If you need, I have the 15 Heliar, 25 Biogon and 28 Biogon.. can post some samples on the -5N.. The center portions are outstanding especially with the Biogons, the edges and corners however are not up to the same level but still better than the samples in the website above.

If you want reproduction-lens quality with such sensors then the SLR lenses are the prime choice, for example the Summicron-R 35/2 (E55); due to the longer register distances it does not matter for them if the sensor is equipped with offset microlenses or not.

[semilog]

This Zeiss document deals with a bunch of the issues under discussion here.

http://blogs.zeiss.com/photo/en/wp-c...s_Distagon.pdf

Bottom line is that microlenses matter, and thin sensor cover glass may matter even more.

That said, for a lot of purposes I think we overemphasize the importance of sharp corners, especially on wide RF lenses where there is enough vignetting that the corners are often dark anyway. Much depends on the subject and the intended use of the pictures, of course. Perhaps one reason why we care so much about sharp corners is simply that we've spent a lot of money buying lenses that in principle can render sharp corners. Sometimes those corners really are important for a strong image, but more often, in an awful lot of really good pictures, no one cares what the MTF looks like in the corners.

[rbelyell]

is it just CA and corner performance? or is it lack or detail throughout the frame as well? i'm just asking what people observe, because i can live with unsharp corners, i cannot live with lack of clarity and detail.

[semilog]

The ZM 21 MTF comparison in that Zeiss document that I linked above does not specify who manufactured the sensor that is not a Leica sensor, but given that it was published in Dec., 2011 I am going to venture to guess that it might be the NEX-7. If that's the case, the 21 takes a very serious hit from about 35% of the field out. That is consistent with my experience using the 21 on the X-Pro. That lens is acceptable in the central 2.3 or so from about f/5.6 and smaller but nothing like what it can do in an M loaded with ACROS or Ektar 100.

The ZM21 seems especially problematic with sensors other than the Leica ones. I don't have data for other lenses. My impressions of the CV 15/4.5 are that it does better than the ZM21/2.8. But of course it vignettes more (which helpfully deemphasizes problems at the periphery) and it starts at f/4.5, not f/2.8.

It's worth noting that the RD-1 does not have offset microlenses and to my knowledge there's not as much worrying about its corner performance as with the NEX cameras and the X-Pro. I'm not sure whether this reflects the RD-1's lower pixel count, lower expectations when it was released, or genuinely better performance with legacy wide angle lenses versus the NEX-7 and X-Pro1.

[gavinlg]

You'd be better off with something like an OM or nikkor 24mm. They won't smear as much being SLR designs with the rear element further away from the sensor. Way cheaper too.

[Matus]

If they say that results with 25/2.8 are bad - I do not understand. That lens has retrofocus design (is rather long) - so it should work reasonably.

I have only seen issues on APS-C sensors with lenses 21mm or wider.

So than Ricoh GXR it is ...

[Jamie Pillers]

Originally Posted by Shutterspark

No personal experience, but when researching the same thing myself I did come across this:

http://www.flickr.com/groups/zeissik...7630553445286/

Doesn't look very promising.

In the example thread you've provided, not one of the people posting comments included an example of the "bad" images they refer to. That whole thread just sounds like a bunch on uninformed 'group-speak' so common on the web these days.

[aleksanderpolo]

The Biogons are not retrofocus, the distagons are. They do not have problem on GXR though, not even the CV 15.

The link posted above is the best test so far of the M's performance on XP1:
http://picabroad.com/2012/03/24/fuji...-mount-lenses/

By the way, the comment on the "group-speak" can also be applied to the current thread as none of us is showing first hand full crop

Back to ZM 25, saw this set on flickr which is a comparison of x100 with XP1+ZM25, doesn't look bad actually:
http://www.flickr.com/photos/nickdem...7629648785976/

[semilog]

^-- thanks for posting that! I maybe can post some xpro + 21/2.8 biogon and 35/2.8 c-biogon stuff within a couple of days once I get these web servers migrated to new server hardware. :-(.

[.... _]

I would have thought that because the zm lenses are designed cover full format 135, by using on a smaller format sensor you will only be using the central portion of the lens and the obliqueness of lightray angles would be reduced in the corners to less than on an M9. So I'm surprised its a problem.

[rbelyell]

Originally Posted by aleksanderpolo

Back to ZM 25, saw this set on flickr which is a comparison of x100 with XP1+ZM25, doesn't look bad actually:
http://www.flickr.com/photos/nickdem...7629648785976/

Hi alex

i took a look at the flickr site, thanks. while i do think it is very hard to draw conclusions from that downsized site, what immediately came to my mind was how darned good the X100 is! to my eye in this series it was at least the equal to, if not sometimes superior to, the xpro/zeiss combo that costs well over twice as much. did you see it that way?

i'm also curious as you mentioned the gxr, are you using that camera? if so, does the quality you get from it 'immunize' you from xpro/rf GAS? i ask this because i'm presently considering both systems to work with my RF lenses. i keep struggling with this because the fuji sensor is just so special, but the gxr is optimized for RF lenses...
tony

[semilog]

Originally Posted by rbelyell

Hi alex

i took a look at the flickr site, thanks. while i do think it is very hard to draw conclusions from that downsized site

There are links to full-size JPEGS (for at least some of the images) in that flickr set. And I agree -- the X100 is an amazing little camera. Shows what you can do if you design a sensor and a lens as an optimized system rather than as separate modular components.

[semilog]

Originally Posted by tog

I would have thought that because the zm lenses are designed cover full format 135, by using on a smaller format sensor you will only be using the central portion of the lens and the obliqueness of lightray angles would be reduced in the corners to less than on an M9. So I'm surprised its a problem.

A lot of M-mount wide angle lenses have rear nodal points very close to the film, and small exit pupils. At the corners the light is coming in at very shallow angles of attack, even in an APS-C crop. The Zeiss PDF linked above shows MTF data for the ZM 21/2.8 in APS-C crop. It's a real problem.

[aleksanderpolo]

Hey Tony,

The GXR definitely quenched my desire to get the XP1 for M-lenses. The focus assist mode 2, the three different magnification (2x,4x,8x), the more responsive EVF (the one that olympus used), the microlenses optimized for wide M (the CV15 on GXR has sharp corner at f8 at 100% crop, you can check the picabroad link and see that it doesn't on XP1). Only drawback is that it has slow buffer and slow shot to shot time, and of course its high ISO is not as good as Fuji. But at base ISO it has a clarity that is stunning, due to the lack of AA filter and the use of traditional bayer layout.

The appeal of XP1 to me is primarily the native 35/1.4. Hey, perhaps you can rent them both to see it for yourselves, as you will be using primarily M-lenses? Different people have different expectation/requirement of sharpness. I don't think these kind of "it's sharp enough" "No it's not" discussion is going to settle it for you.

[rbelyell]

alex thanks so much. i really respect your opinion, and i am getting to a point where i am very close to agreeing that if i want to continue using RF lenses its probably, unfortunately, not going to be with the xpro. my decision now is whether i want to abandon RF lens/digi use in favor of the xpros outstanding IQ with native lenses. maybe i do need to invest some money in rentals...

i guess i could also continue to use 40mm and above RF lenses on the xpro...):
tony

[.... _]

If fuji are listening maybe they will do something about it on the x-pro2 2.5mm seems awful thick for a filter on a sensor. Only now they have lenses designed for it maybe not

[semilog]

I expect that there are good technical reasons why that cover glass is so thick. I don't pretend to know what those reasons are, though.