CV 15 on film vs. CV 12 on M8?

[Dante_Stella]

I did a lot of shooting with my CV 15mm lens on my Hexar RF over the weekend and really liked the results (at least on XP2 Super). Is a CV 12mm roughly the same thing on an M8?

Please note, I am not asking about focal length conversion coming out to being roughly the same thing. Doing the math is how I got to the question! 🙂

My interest is in whether the linear distortion and vignetting are similar.

Any perspectives from anyone who has used the 15 on a film body and a 12 on a digital body would be appreciated.

Thanks!
Dante

 

[Artorius]

I did a lot of shooting with my CV 15mm lens on my Hexar RF over the weekend and really liked the results (at least on XP2 Super). Is a CV 12mm roughly the same thing on an M8?

Please note, I am not asking about focal length conversion coming out to being roughly the same thing. Doing the math is how I got to the question! 🙂

My interest is in whether the linear distortion and vignetting are similar.

Any perspectives from anyone who has used the 15 on a film body and a 12 on a digital body would be appreciated.

Thanks!
Dante

I have just recently acquired the 15, and have used it on the M8 and M/3/4mp. haven/t processed the film yet, but with the M8, everything is looking good,

 

[Ben Z]

Hi Dante. Always enjoyed your site/articles. Hope I can help here. I've had the 15 since it first came out, so I've used it on film for quite a while. I bought the 12 when I found a good deal on one used, basically intending to save it for a digital M which I figured would have a crop factor, to assume the duties the 15 had on a film body. Naturally I did shoot it on film, but only a little, as I really find it way too wide for any use I have. Initially my foray into M digital was an Epson R-D1, but now use both lenses on the M8.

The 15 was always a great lens, but it's even better on the M8 than on film, although it was worse (awful vignetting) on the R-D1. The M8 crops the part of the image where most of the 15's distortion and aberrations are. (It does that with all lenses, leaving the "sweet spot", which is one reason I prefer cropped sensors to full-frame). As I said, vignetting on the M8 is very well-controlled, which was a pleasant surprise after the R-D1.

The 12 is probably a better-corrected lens than the 15. At least, I found it so both on film and digital. Oddly it vignetted much less than the 15 on the R-D1. On the M8 they are both about the same. Again, the M8 crops the worst part of the image circle and leaves the best. Like the 15, if you have the 12 tilted off axis at all, you're bound to get distortion, but with everything square to the world, my experience is that the 12 is probably the more rectilinear of the two.

The biggest advantage to the 15 is the ergonomics. It's small, and it's easy to DIY filter threads to accept an IR filter that won't vignette even with film bodies. No need for expensive aftermarket filter holders. I'm still experimenting with the 12. I have Cosina's 77mm filter adaptor for it, and a 77mm IR filter, but I'm planning to experiment with epoxying an empty filter mount inside the little lens shade, which would take a smaller filter. Similar to what I did with the 15.

One other disadvantage with the 12 is that so far I've been needing to use PanoTools to correct the cyan corners resulting from the IR filter. It's not a big deal but it is an extra step. I've been meaning to try it using the WATE-coded adaptor off my 15 to see how the 16mm setting looks. It would be great if it worked.

 

[nksyoon]

It's small, and it's easy to DIY filter threads to accept an IR filter that won't vignette even with film bodies. No need for expensive aftermarket filter holders.

I use a 39mm IR filter from Leica wedged inside the lens hood with a thin piece of rubber.

One other disadvantage with the 12 is that so far I've been needing to use PanoTools to correct the cyan corners resulting from the IR filter. It's not a big deal but it is an extra step. I've been meaning to try it using the WATE-coded adaptor off my 15 to see how the 16mm setting looks. It would be great if it worked.

I fix cyan corners from the 15 with Cornerfix, works well.

 

[kbg32]

Dante, I have both and use them on the M8. I like the results of the 12 on the M8. I have not been happy with the 15 - it distorts and has lots of fall-off. Maybe it is my example. The 12 is really stellar and gives the same angle of view on the M8 as the 15 does on a film body.

12mm-
http://www.rangefinderforum.com/photopost/showphoto.php?photo=71477
http://www.rangefinderforum.com/photopost/showphoto.php?photo=69962
http://www.rangefinderforum.com/photopost/showphoto.php?photo=54938

 

[Ben Z]

I use a 39mm IR filter from Leica wedged inside the lens hood with a thin piece of rubber.

I took the glass out of a 39mm B+W filter and ground the male threads flush with the mount, then epoxied it inside the lens hood. Basically I added the female filter threads that are missing. Screwing on the IR filter does not vignette on the M8, and the expoxied filter mount by itself doesn't vignette on film so the lens is still suited for use on my M4. The only issue I'm having is that I followed what I read and used a Leica-branded IR filter, which come to find out is aluminum, and now it's stuck. I hope I can unscrew it without pulling my epoxied threaded ring loose. From now on I'll use a B+W IR filter instead.

I fix cyan corners from the 15 with Cornerfix, works well.

Cornerfix is a great software, but it's an extra step that I don't need with any other lens. The reason I use Panotools is because it's a PS plug-in and I can use it after I've done the conversion from DNG and bunched all the 12mm shots together. If I had numerous uncoded lenses I needed to correct in software, then for sure I'd use Cornerfix.

 

[Photon42]

I took the glass out of a 39mm B+W filter and ground the male threads flush with the mount, then epoxied it inside the lens hood. Basically I added the female filter threads that are missing [...]

Hi Ben, I like the idea.

Regards
Ivo

 

[Nick De Marco]

I too have had both. The 12 is too wide on film in my opinion - I bought it for the M8 where it is pefect. I thought the 15mm was a cracking lens, ut I think I prefer the quality of the 12 too. I've now sold the 15.

Here are some with the 12

 

[meven]

Hi,

Ben Z, could you show us a picture of the hood with the filter?

Thanks

I took the glass out of a 39mm B+W filter and ground the male threads flush with the mount, then epoxied it inside the lens hood. Basically I added the female filter threads that are missing. Screwing on the IR filter does not vignette on the M8, and the expoxied filter mount by itself doesn't vignette on film so the lens is still suited for use on my M4. The only issue I'm having is that I followed what I read and used a Leica-branded IR filter, which come to find out is aluminum, and now it's stuck. I hope I can unscrew it without pulling my epoxied threaded ring loose. From now on I'll use a B+W IR filter instead.



Cornerfix is a great software, but it's an extra step that I don't need with any other lens. The reason I use Panotools is because it's a PS plug-in and I can use it after I've done the conversion from DNG and bunched all the 12mm shots together. If I had numerous uncoded lenses I needed to correct in software, then for sure I'd use Cornerfix.

 

[jan normandale]

heh, I was going to suggest you contact Keith / kbg32 ; check his images.

 

[HenningW]

I've had both lenses since they came out, and have used both extensively on film and digital. On the 15 I use a Milich LT-M adapteer and jam a 39mm filter into the 'hood' and on the 12 I use the 77mm adapter and filter. Here you have to watch that you put a ring of black paper between the filter and adapter so that you don't get reflections off the back of the filter through the cutouts in the adapter.

The 15 is coded as a WATE, and the 12 gets corrected with Cornerfix. Both work well on film or digital (M8). The 15 had a LOT of vignetting on the RD-1, though and definitely more than the 12.

Yes, the 12 on digital works as well as the 15 on film, except that you should not use f/11 or 16 on the 12 as those apertures introduce way too much diffraction loss, whereas f/11 is still useable on the 15.

The 12 with Cornerfix has of course essentially no vignetting, whereas the 15 on film definitely does. Distortion is essentially the same; ie, very slight. I'm not sure what the previous poster saw w.r.t. distortion on the 15, but it is not a sample variation. Distortion is one of the basic design parameter results and will not vary between samples.

John Milich makes a filter adapter for the 12 that uses a smaller IR/UV cut filter, but I haven't tried that. It should make the lens a bit handier, but it would cost me an additional $300 or so when I already have a useable solution.

I generally use Heliopan filters as I found a source that could provide them at a much lower cost than B+W or Leica, and they are all low profile.

The WATE finder is quite good with the 12 and WATE, or 12, 15 and 21 as it has framelines for all the combinations on the M8 and a bubble level, so I use it regularly in spite of its apt 'Frankenfinder' moniker.

Henning

 

[Bébèrt]

Here's a pict taken with my UltraWide 12mm and the M8.
No fix with cornerfix for the vignetting.
Look's much like the superwide 15mm witch I have used with my Bessa R2M but the 12mm is even sharper.

 

[Ben Z]

Hi,

Ben Z, could you show us a picture of the hood with the filter?

Thanks

Ask and you shall receive 🙂

 

[Hephaestus]

I cannot speak to the results on digital but my experience is that the 12mm is every but the optical equal of the 15mm based on my slides. The really great thing about using the 12mm on the M8 is not having to use the huge 12mm finder! I also felt that it was slightly superior to the 15mm lens in both build quality and ergonomics. Sounds like a natural, to me!

 

[kbg32]

heh, I was going to suggest you contact Keith / kbg32 ; check his images.

Thanks for the recommendation Jan!

Cheers!

 

[Photon42]

Ask and you shall receive 🙂

Nice indeed. May I ask if it shows vignetting on a film body?

Regards
Ivo

 

[summilux]

the 12mm rocks on M8, i used it without filter or coding, it is better made than the 15mm too.