Minolta MD 50mm f2

[Bigtiki]

On 7/14/2005 at 6:19 AM, larry h. said:

Hi Ivan,

 

Thanks for the detail. I wanted to clarify one statement. You said, "Best of all by a small head was the 50 mc rokkor 1.7 (not the one without the rokkor in the title)." To the best of my knowledge, there is no MC version without the Rokkor, only an MD non-Rokkor. So you do mean the 50mm/1.7 MC Rokkor(-X), right?

 

I know none of these lenses (beside an f/1.2) is expensive. I just want to try to eliminate testing them all myself. What I am looking for is an astrophotography lens I can use wide-open. I usually use f/2.8 as a standard aperture, but it would be nice to be able to use a wider aperture to get more stars (# stars is dependent on the absolute aperture in mm) while using a shorter exposure to avoid tracking, reciprocity and sky fog. That would mean little or no light fall-off or astigmatism/coma in the corners and no spherical aberration in the center. Such a lens probably does not exist.

 

I have the 58/1.2 (which I have not tested but probably is not great for astro work) and the 58/1.4 (which was sharper than my former MC 50/1.4 at f/2.8 in a test of the specific two lenses I had; by most reports, I may have a particularly good copy of the 58). I would be willing to swap out the 58/1.4 for the MC Rokkor(-X) 50/1.7 if there's a chance the 1.7 is better at f/1.7 and f/2.8 both.

 

I just guess I'll have to buy the MC 50/1.7 from KEH and try all three together. Then, I will continue waiting for a clear night in my neighborhood.

I just purchased an MD 50mm f2 (no sign of Rokkor or X), and I have a Minolta 45mm pancake. I had, and used (manually) a Nikkor 50mm F1.8 D (first gen autofocus) for astro. I also purchased the slightly different formula 50mm F2 ais. Upon testing, I found the Nikkors were the only ones that I would use in future. The 45mm pancake was still wanky and soft with coma at borders at F5.6. The Minolta 50mm F2 was borderline acceptable at F5.6, and the two Nikkors were almost imperceptibly different at f5.6, and could be used at F4.5, but still better at f5.6. Of course this means you must use a star tracker because 4 seconds is the limit before orbital smearing starts. The 50mm F2 Nikkor has simpler stars because it has 6 blades while the f1.8 D has 7, which means more star points but slightly more diffusion. I'll be using the F2.0 Nikkor.

[rodeo_joe1]

On 12/20/2022 at 3:01 PM, Bigtiki said:

a Nikkor 50mm F1.8 D (first gen autofocus)

The AF-D is actually the 3rd generation of Nikon AF lenses, and given the lack of a hard infinity-stop and short focus throw, it's one of the last lenses I'd choose for astro photography. The Chinese made AF-D also suffers from a rather sloppy build quality and quality control, making the all-metal pre-AI or AI 50mm f/2 Nikkor H a much better choice. The manual focus Ai-S 50mm f/1.8 Nikkor is also pretty good at f/2 and smaller apertures. 

The AI or AI-S  f/1. 4 Nikkor S-C has even better corner definition and a flatter field - not at f/1.4 though, it needs stopping down to f/4 for near-optimum corner-to-corner definition. 

Better yet, if you can find one, is an MC ('green' coated) Chinon 55mm f/1.4 lens. Yes, Chinon! My sample has better field flatness and corner definition, and from wide-open, than any other 50-58mm lens I've yet been able to lay hands on.

FWIW Chinon's 55mm f/1.7 version isn't anywhere near so good. 

 

[rodeo_joe1]

On 2/26/2023 at 2:55 PM, rodeo_joe1 said:

Better yet, if you can find one, is an MC ('green' coated) Chinon 55mm f/1.4 lens. Yes, Chinon! My sample has better field flatness and corner definition, and from wide-open, than any other 50-58mm lens I've yet been able to lay hands on.

Update on the above. For years I've owned a Zeiss 50mm f/1.8 Planar in Rollei QBM mount, but had no working camera to use it on. However I recently bought a QBM adapter for the Sony A7r4 and so have been able to put the Zeiss Planar through its paces. I'm impressed... very impressed. Corner sharpness is very good wide-open, and comparable to the Zeiss/Sony 55mm f/1.8 Sonnar. In fact the LoCa fringing of the old Planar is far less than that of the far more expensive Sonnar, but it does show a slight amount of spherical aberration wide open. This disappears at f/2.8 and the two are pretty much equal from there on. 

BTW, the Rollei/Zeiss Planar is nothing like the original double-Gauss 6 element Planar. It's an asymmetric 7 element design with a Gauss-type rear section and 4 separated elements in front of the iris.

I'd certainly recommend the Sony/Zeiss ZA 55mm Sonnar for astro work with a Sony MILC, but if you don't have that sort of money to spend, then the Rollei Planar can be got used for well under half the price of the Sonnar. 

Edited February 18 by rodeo_joe1