Photar 2/25 + "relay lens" = Surprise

[Macrero]

I owned a few of those over the years and I never put them to good use, because of poor coverage at relatively low magnification and at "sweet" f/stop.

I currently own the 2/25 only. The other day I was re-testing and playing with optics I have not used for years. Unfortunately, lenses are not like wine and its quality does not improve with the years The Photar 2/25 gave a good center resolution, but coverage/corner performance at 3.5-5X was poor without stopping it down too much.

So, it may sound like a stupid idea, but I decided to give it a try mounted on top of a Raynox 250. Ta-daah! At 3.1X (M I get at shortest bellows extension) and f/3.2, coverage was nearly perfect, center performance remained the same, I would say it slightly improved as well Better than what I get from the Mitty 5 at similar magnification.

Here is a quick test stack at 3.1X and f/3.2 (APS-C):

https://easyzoom.com/image/129606

I have no idea why that behavior. Design is not symmetrical, so you can not assume it is working as stacked lens, it is not an infinity corrected either, also the Raynox was focused far from infinity.

Best,

- Macrero

[Lou Jost]

Great find! (had to take your word for it though, I get a 404 error on your linked page). The world is far more complicated than we knew, and that's exciting. As Robert said recently, we all might have hidden gems laying around in our junk drawers, if only we knew which pieces of junk to combine....The Raynoxes are often a good ingredient though.

[Macrero]

Lou,

try again, you should be able to see it now. I realized I didn't mark the photo as "visible for everyone".

Yep, it is one of my favorite hobbies to try "unknown" optics, designed for... whatever. Truth be told, in the vast majority of cases it is a miss, but there are hits as well.

I always try the lenses I know little to nothing about in every possible way, straight mounted, reversed, as stacked lens, as infinity lens, with f/stop (if the lens has fixed aperture), etc...

In this case, the lens is far from unknown, and it is designed to work straight mounted on bellows. That's why I had never thought of trying it in a different way (till now) and the reason for my surprise.

- Macrero