You like your 50’s.
It's true... I'm past 50 in Leica mount...
You like your 50’s.
You can never own too many 50mm lenses. I don’t have 50!50mm lenses, but I may have 30 or so.
Chromatic Aberration should be measured as focus shift across the spectrum from the primary point of focus. Measured at the out-of-focus areas on a blown out Digital image is meaningless, except to decide if you like a lens or not.
APO lenses are best used on a Monochrome Camera or Black and White film. This is where using Color Filters has a big impact on focus.
Pentax 85/4.5 Ultra-Achromatic lens on the M Monochrom, UV and Red filters.
Pentax 50/1.4 Syper-Takumar, converted to M-Mount and RF coupled, on the M Monochrom.
Yellow filter:
Red filter.
Color pencils representing the Spectrum. Roy G Biv. Similar "debate" on LUF 5 years ago- I took these images.
Full res images here:
https://ibb.co/album/tmmWP1
What's the point? Chromatic Aberration causes focus shift similar to Spherical Aberration. On a color camera, some can be eliminated in Post. On a Monochrom camera, it must be eliminated Optically. Most lenses shift towards infinity with deep color filters.
So- this was a 15 minute test of the 50/1.4 Pentax that runs ~$50 and the Pentax 85/4.5 that today cost about the same as the Leica APO-Summicron.
Sidenote: Purple Fringing on a Digital Camera- some can be attributed to IR contamination. I use IR cutfilters on my faster lenses with the M9 to greatly reduce purple fringe.
Thankyou, CBoy- I appreciate that.
When the APO-Lanthar arrives, I'll do a similar test. I can use the same filters, the Pentax lenses and Lanthar all take 49mm filters! I'm set.
I had a "Random thought"- the APO Summicron was introduced with the original M Monochrom, which used a CCD. CCDs do better than CMOS with light coming in at steep angles. All newer cameras, including Leica, now use CMOS. The APO-Lanthar has a longer optical path, side-effect: it is a bigger lens. I wonder how much of optimizing the new lens for CMOS sensors went into the design, and how much the original APO-Summicron relied on a CCD being used.
Chromatic Aberration should be measured as focus shift across the spectrum from the primary point of focus. Measured at the out-of-focus areas on a blown out Digital image is meaningless, except to decide if you like a lens or not.
APO lenses are best used on a Monochrome Camera or Black and White film. This is where using Color Filters has a big impact on focus.
Pentax 85/4.5 Ultra-Achromatic lens on the M Monochrom, UV and Red filters.
Pentax 50/1.4 Syper-Takumar, converted to M-Mount and RF coupled, on the M Monochrom.
Yellow filter:
Red filter.
Color pencils representing the Spectrum. Roy G Biv. Similar "debate" on LUF 5 years ago- I took these images.
Full res images here:
https://ibb.co/album/tmmWP1
What's the point? Chromatic Aberration causes focus shift similar to Spherical Aberration. On a color camera, some can be eliminated in Post. On a Monochrom camera, it must be eliminated Optically. Most lenses shift towards infinity with deep color filters.
So- this was a 15 minute test of the 50/1.4 Pentax that runs ~$50 and the Pentax 85/4.5 that today cost about the same as the Leica APO-Summicron.
Sidenote: Purple Fringing on a Digital Camera- some can be attributed to IR contamination. I use IR cutfilters on my faster lenses with the M9 to greatly reduce purple fringe.
I think Head Bartender here still has CV 2,5/90 APO LTMs in stock. Not like they don't already exist.
Since any of these makers plan long ahead of time, the M240 was likeliy finalized by the time the 50 APO and M9M appeared. Given its resolution, the design was for future high res cameras in mind and at the tine, the M9M was best able to showcase it. Not unlike the M10M.
The 90mm APO is an f3.5, not f2.5. It’s also a 20 year old lens and only came in LTM.
Not knocking the lens (I’ve heard it’s great), but not quite the same as a new, m mount ~f2.5ish 90mm. This remains a segment of the M ecosystem without a lot of options, especially if you won’t/can’t pay for a Leica.
This lens has floating elements, and correction elements. Without having the precise prescription of the lens and putting it into a program that does optical modeling, hard to know exactly what it will do. Any amount of CA in the plane of focus will blur the image that cannot be corrected on a monochrome camera. An interesting test would be to use different color filters with a color test target, like color streamers running perpendicular to the camera.