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Mirror lenses (2)

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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 30 October 2022 at 20:10
Originally posted by anthills 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
Miranda F & Sensorex, Sony A7Rii, A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras ...
 



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woodrim View Drop Down
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Post Options Post Options   Quote woodrim Quote  Post ReplyReply Direct Link To This Post Posted: 30 October 2022 at 22:53
I've been out of the corporate environment for nearly 24 years but remember when working with quality methodology, it was always essential to have metrics. With regard to quality, it wasn't good enough to say I know it when I see it. However, today when using lenses, I'm quite satisfied with making my judgments based on what I see from a lens. The MTF is much less important to me since it is acquired in a controlled manner and doesn't take into consideration other important (to me) factors such as ease of use, feel, and whatever else satisfies my needs visually.

Yes, sharpness is important. I realize that most photographers don't enjoy the mirrors as much as I do and most value the near perfection of modern-day lenses. I love using mirrors and have quite a few that I have used extensively. My favorites are the ones that have given me the best overall performance and feel. They are also sharp lenses, relatively speaking, but have other characteristics that I value just as much. Sometimes, I may not be able to put my finger on the reason, but I know what I like when I see it. Some have pleasantly surprised me while others have disappointed. My appreciation does not always match the lens' reputation.   
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woodrim
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neilt3 View Drop Down
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Post Options Post Options   Quote neilt3 Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 00:46
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 .

[/url]
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
see my photostream on flickr;
http://www.flickr.com/photos/neilt3/
C & C welcome.
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Brownie View Drop Down
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Post Options Post Options   Quote Brownie Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 02:14
Interesting thread. I picked up a Minolta 500 this spring, and after basic testing and being pleasantly surprised with the IQ I decided to try using it for action, something I haven't seen much with reflexes. There was a carnival in town so I walked down the street.

Had a lot of misses right off, I had forgotten that the lens uses the center focus area only, so I had to up my panning effort. Once I stopped being lazy the hit rate went way up. These were with the A7M4 and LA-EA5.

DSC02023 by telecast, on Flickr

DSC02037 by telecast, on Flickr

DSC02128 by telecast, on Flickr
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Miranda F View Drop Down
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 08:22
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!
Miranda F & Sensorex, Sony A7Rii, A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras ...
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Post Options Post Options   Quote Howard_S Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 09:11
I hadn't thought of using the 500 when the fair came to our town a couple of months ago - well done, and I hope I remember next year!

I took the Vectis 400 out with the LA-VE1 on an A5000 the other day ...


Colour and bokeh

and blurring because of the relatively low shutter speed (1/320s) and no IBIS.

The next I put into my Photo 150 thread


If you go down to the woods today ...

A suitably spooky feel for Halloween?
Howard Stanbury Instagram | Flickr | Web
 



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Brownie View Drop Down
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Post Options Post Options   Quote Brownie Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 12:11
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!
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Post Options Post Options   Quote Brownie Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 13:39
A couple more that surprised me. These are with an A7RM3 and a generic Kalimar 1.4 TC, so MF. The IQ in these was kind of a shock with this combination. If the second photo looks a bit soft, the center of that bridge railing is 1845’ away per Google Maps, or over 1/3 of a mile.

52057813014_15d668c7f5_o by telecast, on Flickr

52058063655_8d486b9b8f_o by telecast, on Flickr
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anthills View Drop Down
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Post Options Post Options   Quote anthills Quote  Post ReplyReply Direct Link To This Post Posted: 31 October 2022 at 17:04
Originally posted by neilt3 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?
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neilt3 View Drop Down
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Post Options Post Options   Quote neilt3 Quote  Post ReplyReply Direct Link To This Post Posted: 05 November 2022 at 23:41
Sony a6600 , Minolta Vectis 400mm f/8 Reflex , Monster Adapter LA-VE2 .


Smoke and clouds , November moon .
by Neil , on Flickr


Smoke and clouds , November moon .
by Neil , on Flickr
see my photostream on flickr;
http://www.flickr.com/photos/neilt3/
C & C welcome.
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neilt3 View Drop Down
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Post Options Post Options   Quote neilt3 Quote  Post ReplyReply Direct Link To This Post Posted: 06 November 2022 at 00:29
Originally posted by anthills anthills wrote:



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?


Erm , well , how can I put this ....
It wasn't Minolta messed my lens up , it was me !

I've had another look at the baffle , and had a look at the ones on all my other Vectis lenses ( I've got at least a couple of dozen ) and I realise what's happened .
A few years ago I had a look at altering the baffle to trim it to cut down on the cut-off / vignetting on a full frame sensor .
Turns out what I'd done ( and forgot about ) was rather than chop up the original baffle , I took one out of a 22-80mm lens that was faulty and chopped bits off that rather than cutting up the original .

The issue with the lens and baffle is that the baffle is needed to hold the electronic contacts , so has to stay . When you focus closer (IIRC) the rear lens element recedes up the barrel and as the baffles are basically a tube , this is what causes the problem .
The rear element of the 22-80mm doesn't recess anywhere near as much as the 400mm , that's why the tube isn't flocked .

Regarding a fix , I'll sand down the tube so it doesn't reflect the light and that'll sort it , though I'll still have the original baffle somewhere .
see my photostream on flickr;
http://www.flickr.com/photos/neilt3/
C & C welcome.
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woodrim View Drop Down
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Post Options Post Options   Quote woodrim Quote  Post ReplyReply Direct Link To This Post Posted: 15 November 2022 at 19:44
I'm glad to see others out enjoying their mirrors.

I read that some of you with the LA-VE2 adapter have had trouble getting the 25-150 working. In my initial test, It worked for me, but then this past weekend I put it on and could not get it to work. I remembered what I did with another lens to get it working, so took both the lens and adapter off the camera with the camera powered off. I put the adapter back on with a firm snap into place, then the same with the lens. It started working and I had a good experience with it. Aside from the vignetting, I very much like what I got from the lens. The solution suggests the adapter may be having some issue with the contacts and the firm mounting corrects it. Make sense?

These are all mirror images from three different lenses.

1 - Vectis 400mm


2 - Vectis 400mm


3 - Vectis 400mm Five image merge


4 - Minolta AF Reflex 500mm


5 - Minolta AF Reflex 500mm


6 - Vivitar Series 1 Solid Cat 800mm
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woodrim
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Post Options Post Options   Quote Brownie Quote  Post ReplyReply Direct Link To This Post Posted: 15 November 2022 at 23:59
The pelican shots are amazing!
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woodrim View Drop Down
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Post Options Post Options   Quote woodrim Quote  Post ReplyReply Direct Link To This Post Posted: 16 November 2022 at 00:05
Originally posted by Brownie Brownie wrote:

The pelican shots are amazing!


Thank you.
Regards,

woodrim
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