Mirror lenses (2)

neilt3 wrote: These are a couple taken today as test shots after I've changed the rear baffle . AF is spot on now and the flares gone.

neilt3, I’d be interested to hear more about how you modified the baffle on the Vectis 400. Was there a problem on your specific copy, or do you think all copies are similarly impaired?

Thanks gents! I figured you couldn’t have much more fun than an AF Reflex. What’s weird is the distance I shot those from. I think you could use it for street photography and shoot from the next block!

@Howard_S, that second shot is definitely spooky!

Wow! Amazing pictures, Brownie, and thanks for sharing them!
It's certainly an inspiration - I've never thought of using the Reflex for that; I shall have to try it myself!

Taken at Manor Park in Glossop , Derbyshire .
Taken with the Minolta Vectis on a Sony a7Riv with the new AF Monster adapter LA-VE2 .
Turned out the problems I was having with this lens and the adapter in general was partly resolved by going into the settings on the camera , ont format , and then Initialise .
The other reason I was having a problem was the rear light baffle was doing anything other than that . It had a gloss finish , so was causing flare and light scatter , reducing contrast and confusing the AF .
These were taken before I fixed this with manual focus .

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Fuchsia by Neil , on Flickr


Autumn Rose by Neil , on Flickr


Goose ? by Neil
, on Flickr

These are a couple taken today as test shots after I've changed the rear baffle .
AF is spot on now and the flares gone .
Camera used is the Sony a6600 .


Autumn Leaves #1 by Neil , on Flickr

anthills wrote: I've been doing some testing of the Vectis 400 and Minolta/Sony AF 50 I haven't MTF-tested a lot of comparable lenses yet, so I can't really report how this compares to any of the dozens of other 400-500-600mm mirror lenses someone interested in these two might also consider. I do other types of testing, though, and subjectively I believe these are in the top of the class.

I've tested quite a few mirror lenses, some of them with line-pairs. However I've never been able (or willing) to produce actual MTF curves, being more interested in whether a given amount of detail can be recovered, eg in birds feathers.
The biggest problem with mirror lenses is that the hole in the middle lowers the contrast at medium MTF which makes images look flat, but the resolution is often very good. The Paragon 300mm, Kenko 400, and Tamron 500mm lenses were the best I'd tested until I got a copy of the Minolta 500mm reflex, which beats them all (just) for recoverable detail (lp/mm after processing) at a given object distance (not how lenses are normally tested, I know).
I tend to use mirror lenses to photograph the moon and the Reflex is the easiest to get good results with.

I think it's well worth considering that with digital cameras it no longer makes sense to worry very much about the MTF curve of the lens itself but what you can get from it with processing, which is very heavily dependent on the camera and sensor used and a lot of other things. Go back and read MTF measurements from older lenses taken on Nikon 6 - 12Mp cameras, for example, and you'll find modern kit zooms can do a lot better! With the A7R series, even old lenses can achieve amazing detail due to the system MTF being so much higher.

Edited by Miranda F - 30 October 2022 at 20:16

It was a cloudy sky Mike

And here one with the AF500 reflex