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Rokkor RF 250mm F5,6
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PostPosted: Wed Apr 08, 2020 11:27 pm    Post subject: Rokkor RF 250mm F5,6 Reply with quote

I guess this one is quite uncommon and I red a number of dicussions on the merits of this lens with quite diverging opinions.

Make your own.



PostPosted: Fri Apr 10, 2020 8:02 am    Post subject: Reply with quote

Like 1 small Like 1 small nice!


PostPosted: Fri Apr 10, 2020 10:58 am    Post subject: Reply with quote

Is this the best mirror lens ever made?


PostPosted: Fri Apr 10, 2020 1:57 pm    Post subject: Reply with quote

blotafton wrote:
Is this the best mirror lens ever made?


Not sure. But today the most expensive one. Wink


PostPosted: Fri Apr 10, 2020 4:08 pm    Post subject: Reply with quote

blotafton wrote:
Is this the best mirror lens ever made?


Hardly Twisted Evil . It is expensive now because it is quite rare (not unlike the Tamron SP 350 mm f/5,6). In fact, at the time it was sold, most prospective buyers of mirror lenses favored longer focal lengths and the RF 250 mm f/5,6 was a commercial failure and quickly abandonned while the RF 500 mm f/8 even got a successor with AF. The price of the 250 mm f/5,6 thus mainly reflects rarity and collector's value, the IQ being very good but not outstandingly so.


PostPosted: Fri Apr 10, 2020 4:11 pm    Post subject: Reply with quote

The spooks have the best mirror lenses ever made. Think, Hubble size mirror aimed down at your roof.


PostPosted: Fri Apr 10, 2020 5:01 pm    Post subject: Reply with quote

Alsatian2017 wrote:

Hardly Twisted Evil . It is expensive now because it is quite rare . . .


Thank you for the summation. I certainly understand collector mania, but the prices I see for this lens are amazing!

https://www.ebay.com/sch/i.html?_from=R40&_nkw=minolta+rf+250+5.6&_sacat=625&LH_Sold=1&rt=nc


PostPosted: Fri Apr 10, 2020 5:04 pm    Post subject: Reply with quote

Antoine wrote:
Like 1 small Like 1 small nice!


Antoine you have a quite nice set of Minolta lenses. I have some of them and I remain curious about the ones I do not have, for example the 20mm 2,8 and the 45mm 2,0.

How the 20 compares to common same era wide angles such as Tokina RMC 17 that we both own? The 45 intrigues me. I am found of the focal lenght since I have good memories of 28mm on APSC but I find difficult to justify the 5mm difference with common fifties and the tests I read here and there claiming it is inferior to any 50, at least on full frame.

Any opinion would be highly appreciated.


PostPosted: Fri Apr 10, 2020 5:57 pm    Post subject: Reply with quote

I bought the 20 mm early on and have to admit I loved it (30 mm on aps) for its compactness and built quality and associated it often with a focal reducer (eq 21.4mm) as 30 is not very wide. Of course, a 17 mm (eq 25.5 mm) is a much wider angle and can be used extensively without the focus reducer.
The 45 mm was offered to me, it is very compact and is nicer with full frame or with the focal reducer on aps.

I now use much more my A7Rii than the A6000 which I only take to travel which is forbidden these days.... The rf 250 (eq375mm on aps) offers a great compactness and great images when one controls out of focus rings. Contrast does not seem such a big issue these days with post treatment (sure purists will disagree...)


PostPosted: Fri Apr 10, 2020 9:48 pm    Post subject: Reply with quote

Antoine wrote:
I bought the 20 mm early on and have to admit I loved it (30 mm on aps) for its compactness and built quality and associated it often with a focal reducer (eq 21.4mm) as 30 is not very wide. Of course, a 17 mm (eq 25.5 mm) is a much wider angle and can be used extensively without the focus reducer.
The 45 mm was offered to me, it is very compact and is nicer with full frame or with the focal reducer on aps.

I now use much more my A7Rii than the A6000 which I only take to travel which is forbidden these days.... The rf 250 (eq375mm on aps) offers a great compactness and great images when one controls out of focus rings. Contrast does not seem such a big issue these days with post treatment (sure purists will disagree...)


This is about the 250mm mirror lens - guys, behave please - or make up a separate thread...


PostPosted: Sat Apr 11, 2020 8:27 am    Post subject: Reply with quote

Sorry my fault I guess.


PostPosted: Sat Apr 11, 2020 5:38 pm    Post subject: Reply with quote

Alsatian2017 wrote:
blotafton wrote:
Is this the best mirror lens ever made?


Hardly Twisted Evil . It is expensive now because it is quite rare (not unlike the Tamron SP 350 mm f/5,6). In fact, at the time it was sold, most prospective buyers of mirror lenses favored longer focal lengths and the RF 250 mm f/5,6 was a commercial failure and quickly abandonned while the RF 500 mm f/8 even got a successor with AF. The price of the 250 mm f/5,6 thus mainly reflects rarity and collector's value, the IQ being very good but not outstandingly so.


Maybe it's the short focal length that hides the flaws of the mirror design. I'm impressed by the various samples I've seen from the 250mm. If there is no obvious bokeh in the shot it's not easy to identify it thanks to the good sharpness and contrast.


PostPosted: Sun Apr 12, 2020 11:41 am    Post subject: Reply with quote

blotafton wrote:
Alsatian2017 wrote:
blotafton wrote:
Is this the best mirror lens ever made?


Hardly Twisted Evil . It is expensive now because it is quite rare (not unlike the Tamron SP 350 mm f/5,6). In fact, at the time it was sold, most prospective buyers of mirror lenses favored longer focal lengths and the RF 250 mm f/5,6 was a commercial failure and quickly abandonned while the RF 500 mm f/8 even got a successor with AF. The price of the 250 mm f/5,6 thus mainly reflects rarity and collector's value, the IQ being very good but not outstandingly so.


Maybe it's the short focal length that hides the flaws of the mirror design. I'm impressed by the various samples I've seen from the 250mm. If there is no obvious bokeh in the shot it's not easy to identify it thanks to the good sharpness and contrast.


Here are a two 100% crops from the 43 MP FullFrame Sony A7RII. The first crop is from the center:


The second crop is fro the extreme orner:


No CA corrections were applied.
I'd say that CA correction is pretty well done; detail resolution decreases a bit, but it's still acceptable, even on 43 MP FF. Vignetting is quite pronounced; it may be disturbing (e. g. landscapes) or enhancing the image (e. g. portraits), depending on the subject. Of course on the common 24 MP FF cameras the image quality looks even better!

S


PostPosted: Sun Apr 12, 2020 12:15 pm    Post subject: Reply with quote

Your crop images concur with my impressions although I do not have a 43M pix full frame. I might test it on a 24M pix APSC that is even more demanding.

My feeling is that it is not optimized for short distance and your photo and mine are close to minimum focus distance.

More info to come.


PostPosted: Sun Apr 12, 2020 1:20 pm    Post subject: Reply with quote

lumens pixel wrote:

...

My feeling is that it is not optimized for short distance and your photo and mine are close to minimum focus distance.


That may well be true - however at the moment we have too much "air movements" (sorry, i don't know the correct English term) so i can't really test at infinity ...

S


PostPosted: Sat Nov 12, 2022 7:08 pm    Post subject: Reply with quote

Here's an image taken recently in the Appenzell area of Switzerland. The landscape is pretty pittoresque, with ancient farmhouses
spread all over the hills and mountains. Situated at about 1000m above sea level, and with steep meadows and harsh winters, earning a
living there is not that easy. About 200 years ago, some clever entrepreneurs did start the production of embroideries which soon
became a worldwide success: 110 years ago, 50% of the woldwide production came from the St. Gallen and Appenzell cantons in
Switzerland. Some of those were made in small factories, some in house like this ones.



The Minolta 5.6/250mm mirror lens gives a remarkably good resolution over the entire 24MP FF image. Not only resolution is good, but
there are also no CAs visible (even less than with lenses such as the Nikkor AiS 2.8/180mm or the Minolta AF 2.8/200mm APO G).

Here are two 100% crops from the 24 MP FF image, one from the center and one from the corner (this time a "color development" to
show the missing CAs). Focusing may not be perfect since I didn't use a tripod.





Drawback are visible vignetting (albeit easy to corretct in PP) and, of course, a noisy bokeh (Tibetan prayer flags in front of another farmhouse):



I have taken quite a few more landscape images that day, always with similar results, like this one:


Looking at a 100% crop (contrast increased) we can see the horizon at a distance of about 40 km and a village.
Again not sure if I have been focusing correctly:


This was the frist time I actually took some landscape images with the Minolta 5.6/250mm mirror lens. Would I recommend it over the
4/200mm or the 5.6/300mm? The mirror lens certainly is much lighter, smaller and quite easy to use on mirrorless cameras. Its
resolution is pretty good, although I expect the MC/MD-I 4/200mm to be slightly better when stopped down to f8 (which at the same
time eliminates vignetting). The mirror lens has an excellent color correction, but also some visible vignetting, combined with a reduced
contrast at the image center. This may be an advantage sometimes, as the main subject is highlighted - but it requires some PP work if
the effect isn't desireable.

Certainly the 250mm f5.6 mirror is much better suited for landscapes than the ordinary 500mm f8 mirror lens, which usually is too long
and limited by haze and / or air turbulence.

S


PostPosted: Sat Nov 12, 2022 7:51 pm    Post subject: Reply with quote

stevemark wrote:
Here's an image taken recently in the Appenzell area of Switzerland. The landscape is pretty pittoresque, with ancient farmhouses
spread all over the hills and mountains...


Certainly looks like a nice area!

stevemark wrote:
This was the frist time I actually took some landscape images with the Minolta 5.6/250mm mirror lens. Would I recommend it over the
4/200mm or the 5.6/300mm?
The mirror lens certainly is much lighter, smaller and quite easy to use on mirrorless cameras. Its
resolution is pretty good, although I expect the MC/MD-I 4/200mm to be slightly better when stopped down to f8 (which at the same
time eliminates vignetting). The mirror lens has an excellent color correction, but also some visible vignetting, combined with a reduced
contrast at the image center. This may be an advantage sometimes, as the main subject is highlighted - but it requires some PP work if
the effect isn't desireable.

Certainly the 250mm f5.6 mirror is much better suited for landscapes than the ordinary 500mm f8 mirror lens, which usually is too long
and limited by haze and / or air turbulence.

S


I appreciate you are looking at the technical aspects here, but once you take into account the price difference that question should be easier to answer! (assuming most people don't have your karma when it comes to bargain lens finds... Wink )


PostPosted: Sat Nov 12, 2022 8:49 pm    Post subject: Reply with quote

RokkorDoctor wrote:

I appreciate you are looking at the technical aspects here, but once you take into account the price difference that question should be easier to answer! (assuming most people don't have your karma when it comes to bargain lens finds... Wink )


Yep, you're right - I though most people here know about the price ofthe Rokkor 5.6/250mm mirror ... and would be more interested in actiual performance Wink

Actually my own 5.6/250mm was about twice as expensiva (CHF 100) as my several MC/MD-I 4/200mm lenses (usually around CHF 50). That was when ebay sellings already had reached the CHF 1000 range. After I got my own 5.6/250, I know of two others who got the same lens here in Switzerland for about CHF 100, though ...

Usually I just what is available at a reasonable price - not looking / searching for a certain lens. That keeps my expenditures low ... there's always some coll stuff available at fairly (or even really) low prices.

S


PostPosted: Sun Nov 13, 2022 10:52 am    Post subject: Reply with quote

Like 1 Like 1 Like 1


PostPosted: Sun Nov 13, 2022 11:36 am    Post subject: Reply with quote

Very nice samples everybody Like 1 Like 1 Like 1
Recently I found a Panagor PMC Reflex 300 mm f/5.6 lens. It's tiny, offers a built-in sliding lens hood (much too short, though...) as well as shockingly good IQ from the center to the outmost corners (tested with an A7 II. Thus, it turns out to be a perfect substitute to the Minolta RF 250 mm f/5.6, given that I've never found that lens at a reasonable price.


PostPosted: Sun Nov 13, 2022 8:30 pm    Post subject: Reply with quote

stevemark wrote:

I have taken quite a few more landscape images that day, always with similar results, like this one:

S


Great shot!