Here is another WA lens good for use with the µ4/3 cameras. I read about it earlier but wasn't sure exactly which lens it was. Then this thread popped up over at DPR yesterday, about the CV 12mm Heliar.
The m43 adapters have a focusing wheel on them to drive the lens's focusing gear.
The M conversions install the optical unit in a new RF-coupled focusing helical complete with focus ring.
Hi Thanks.
The latterof the two seems maybe on the expensive side-so to speak?
Kingfishphoto wrote:
Hi Thanks.
The latterof the two seems maybe on the expensive side-so to speak?
Expensive? yes. Cheaper than buying a new (and inferior) Leica 21 Elmarit? Yes. Transplanting the optical group was mostly done for 21 Distagon conversions because it is to this day arguably the single best lens at its focal length ever (Yes, it does outperform the ZM version).
I bought a couple of lens from KEH for about $150 each, really nice images produced on my m43 camera. I purchased couple of adapters from Amazon.com. Pro-grade adapter offered by Fotodiox, I am a happy man now.
I got a jinfinace adapter. Adapter is well made and fits my E-P1 perfectly.
The lens lock is a bit quirky. After some trials I figured out a working technique: a) close down the lens aperture, b) stick your finger as close to the lens as you can and push the release button. The little piece of metal which locks the lens is very sharp and sheds small bronze particles into the camera. The long term solution would be to have an adapter for each lens.
Initially the operation of the focusing wheel was very stiff. A drop of WD-40 resolved the problem. Ergonomics of the focusing is far from perfect. The small wheel is hidden in a very narrow gap between the body and the black bulge on the lens. There are only a couple of hand positions when you can actually reach the wheel. The movement are not very smooth either. It works, it makes possible to focus with good precision, but it is not for manual focusing snobs. I think that a bigger wheel would've been much better.
It all may sound very critical, but in fact I'm quite happy that this solution exists. After I tried the adapter with a 45mm I ordered a 28mm and a 90mm.
The 28mm needed the "ears" trimming. They are just plastic - very easy job (don't let the debris to get into the lens). After this the lens mounts and focuses without problem.
I received this lens yesterday and with today's weather didn't have chance to use it. But I did a quick comparison to my CY 28/2.8. I set up two shots with both lenses - one shot with the object in the middle of the frame and another with the same object in the corner. Each time I focused on the object. All shots were developed in ACR - no noise reduction, sharpening amount 50 radius 1. The gallery of the test shots is here http://tinyurl.com/yzvpf44 (I really should've cleaned this table ). Below are 200% crops
At f/2.8 the Distagon is better in the center and in the corner. The Biogon improves when stopped down and gets marginally better at f/8. This behavior is confirmed by old photodo numbers. The Biogon appears to have some vignetting which didn't quite disappear even at f/8.
Alex wrote:
At f/2.8 the Distagon is better in the center and in the corner. The Biogon improves when stopped down and gets marginally better at f/8. This behavior is confirmed by old photodo numbers. The Biogon appears to have some vignetting which didn't quite disappear even at f/8.
That must be a function of the sensor. I've owned both lenses. On film, the 28 Biogon is noticeably sharper overall than the Distagon -- particularly in the corner of a 4/3rds sensor. With respect to vignetting -- the two lenses are actually quite similar wide open and stopped down. You should not notice a difference in vignetting between these 2 lenses at the corner of a 4/3'rds sensor if there wasn't sensor-related vignetting due to it's inability to handle the angle of the light from the Biogon.
In the film days, for me at least, the Biogon on the Contax G2 was the clear choice over the Distagon on an RTS.
Lotus, you are right - it is a function of the sensor. More precisely, the layers above the sensor introduce some field curvature which deteriorates the corner sharpness.
Today in good light I made more tests with distant objects. The corner performance of this lens on my Olympus E-P1 is pathetic. At f/8 it is worse than my Distagon at f/2.8. Below is the corner crop. Full images are at http://tinyurl.com/yzvpf44.
It is a pity because I had really high hopes for this lens. Other than performance, it is a perfect fit for E-P1.
). Below are 200% crops