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Chiyoko p-rokkor 2.5/75
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PostPosted: Tue Aug 27, 2013 6:56 pm    Post subject: Chiyoko p-rokkor 2.5/75 Reply with quote

Hello!

First image post, lets see if it gets stuck in the anti spam.

I'll share some pics from a Rokkor lens that haven't been tested much. It's a projector lens that can be found on the cute Minolta Mini 35 slide projector. I have simply removed the lens in a non destructive manner and slapped it on an m42 bellows. To make a snug fit I put some duct tape around the barrel and that’s it!

There are at least two versions of this lens, the probably older alu version and a black one with different barrel. I got them both, for good measure. I think it's a triplet design.

With my eos 40d it can focus to about 2.5 meters give or take. Not reaching infinity hasn’t bothered me much.

First a few wide open shots at f2.5, with added duct tape lens hood. Contrast suffers heavily without the hood.













As you can clearly see there isn't much sharpness wide open. I was really curious about stopped down image quality so first I took a piece of paper with something like a f/5.6-7 aperture hole in it. You can see on the first of the following images that bokeh wasn't that good so I made a new wooden aperture, a slice of wood with a drilled hole, taped to the back of the lens. Better bokeh if you ask me.



crop






Cardinal beetle


Beautiful coating




PostPosted: Tue Aug 27, 2013 7:03 pm    Post subject: Reply with quote

Amazing, that's definately an upgrade!


PostPosted: Tue Aug 27, 2013 8:46 pm    Post subject: Reply with quote

Beautiful pictures, thank you! Lens taken from what equipment ?


PostPosted: Tue Aug 27, 2013 9:11 pm    Post subject: Reply with quote

caspert79 wrote:
Amazing, that's definitely an upgrade!


Certainly smother than the first try!



Attila wrote:
Beautiful pictures, thank you! Lens taken from what equipment ?


The pleasure is mine! The lens belongs to the Minolta Mini 35 slide projector.


PostPosted: Sat Jul 30, 2016 2:56 am    Post subject: Reply with quote

Hello Guys, Sorry revive the topic.

I found here in Brazil, one minolta 35 mini projector, but the lens is not this model, has not Chiyoko name, just Rokkor P 75 2.5, is it the same optical / project with similar results? I'm afraid to buy if you do not have the same result in bokeh.


PostPosted: Sat Jul 30, 2016 7:31 am    Post subject: Reply with quote

espirit wrote:
Hello Guys, Sorry revive the topic.

I found here in Brazil, one minolta 35 mini projector, but the lens is not this model, has not Chiyoko name, just Rokkor P 75 2.5, is it the same optical / project with similar results? I'm afraid to buy if you do not have the same result in bokeh.


It is the same, just late one Wink


PostPosted: Sat Jul 30, 2016 7:48 am    Post subject: Reply with quote

Thanks Klaus,

best regards


PostPosted: Sat Jul 30, 2016 2:26 pm    Post subject: Reply with quote

espirit wrote:
Hello Guys, Sorry revive the topic.

I found here in Brazil, one minolta 35 mini projector, but the lens is not this model, has not Chiyoko name, just Rokkor P 75 2.5, is it the same optical / project with similar results? I'm afraid to buy if you do not have the same result in bokeh.


I have this one:


and the lens is nothing like the older version! it glow like hell and has a lot of coma and other abrasion and very low contrast! the center sharpness is OK but i mean center! 2px left and right from center are became horrible (FC problem i guess) Shocked but beside all of those negative sides it has most unique bokeh!

(obviously all image has some degree of PP)





PostPosted: Sat Jul 30, 2016 5:01 pm    Post subject: Reply with quote

Thanks Raxar,

then, I will continue looking for the old version.

Best Regards


PostPosted: Sun Jul 31, 2016 5:16 pm    Post subject: Reply with quote

[quote="Raxar"]
espirit wrote:
Hello Guys, Sorry revive the topic.

I found here in Brazil, one minolta 35 mini projector, but the lens is not this model, has not Chiyoko name, just Rokkor P 75 2.5, is it the same optical / project with similar results? I'm afraid to buy if you do not have the same result in bokeh.


Quote:
I have this one:


and the lens is nothing like the older version! it glow like hell and has a lot of coma and other abrasion and very low contrast! the center sharpness is OK but i mean center! 2px left and right from center are became horrible (FC problem i guess) Shocked but beside all of those negative sides it has most unique bokeh!

(obviously all image has some degree of PP)


It looks like you have the lens mounted the wrong way Smile

In this thread, I tested Staeble Werk projector lens and it looks similar to your pictures when reverse-mounted.
http://forum.mflenses.com/viewtopic.php?t=75105&view=previous


PostPosted: Sun Jul 31, 2016 6:08 pm    Post subject: Reply with quote

+1. There is no reason Minolta will make a lens in such low quality.


PostPosted: Sun Jul 31, 2016 7:09 pm    Post subject: Reply with quote

blotafton wrote:


It looks like you have the lens mounted the wrong way Smile

In this thread, I tested Staeble Werk projector lens and it looks similar to your pictures when reverse-mounted.
http://forum.mflenses.com/viewtopic.php?t=75105&view=previous


it cant be mounted in the reverse because it has fixed helicoid so may be minolta mounted it in the wrong way Smile
thats the mounting situation:




I'll try to monut it in other way and also use lens hood and it didn't get any better: (setup + reverse and normal)











PostPosted: Sun Jul 31, 2016 7:35 pm    Post subject: Reply with quote

This lens is a triplet. It may be the middle element was reversed but I am not sure.


PostPosted: Sun Jul 31, 2016 9:33 pm    Post subject: Reply with quote

Raxar wrote:



I'll try to monut it in other way and also use lens hood and it didn't get any better: (setup + reverse and normal)




Oh, in that case it's strange. Might be as calvin said.

Since I have both the black and silver version I'll compare them side by side.

By the way the first image of your screen looks better on the edges.


PostPosted: Sun Jul 31, 2016 11:56 pm    Post subject: Reply with quote

calvin83 wrote:
This lens is a triplet. It may be the middle element was reversed but I am not sure.


you are absolutely right about something wrong with the elements!Like Dog

it wasnt the 2nd element but it was the spacer between 1st and 2nd! when i try to open the lens the edge of first and second elements are shattered Rolling Eyes some idiot place both spacer between 2nd and 3rd and screw the helicoid bolt on them Twisted Evil re-arranged them and its now comparable to the other 75/2.5 Happy Dog

focus is on the left side


PostPosted: Mon Aug 01, 2016 3:03 am    Post subject: Reply with quote

Good to hear you solved the problem. Congrats Friends


PostPosted: Fri May 24, 2019 2:37 pm    Post subject: Reply with quote

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