New (used) Rokkor 21mm/2.8

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Archive 2008 · New (used) Rokkor 21mm/2.8

cogitech
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p.4 #1 · New (used) Rokkor 21mm/2.8

Myth

The only thing that might come close to the CZ21 is the new Z? version from Zeiss, but I don't have high hopes after seeing what the new ZE 85/1.4 is like.

Seriously, Jim. The CZ21 is just out of this world. Anyone and everyone who has owned or still owns one will tell you.

Think of the sharpest normal or short tele that you can imagine (85L at f4 for instance). The CZ21 is like that from corner to corner at f5.6 only with better microcontrast and huge amounts of 3D effect. It made me shiver the first time I saw the files from it.

Edited on Nov 15, 2008 at 02:51 AM · View previous versions

Nov 15, 2008 at 02:44 AM

JimBuchanan
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p.4 #2 · New (used) Rokkor 21mm/2.8

cogitech wrote:
Myth

I was speaking for Max.

Nov 15, 2008 at 02:46 AM

PhotoMaximum
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p.4 #3 · New (used) Rokkor 21mm/2.8

Like Clint says, "a man has got to know his limitations..."

This is probably doable, but It really looks like I need to bring in help (someone who has a machine mill and skill.) There is also the risk of turning this lens into a paper weight. I bought the lens for $175.

Initially I thought the 58mm conversion would turn into one of those "why did I get into this" moments but the process was fun and it worked like a charm. But Paul's web page was so clear on every step its hard to mess it up. Two pages linked from Jim don't really go into the detail that Paul did on his 58mm page. Sounds like Dimka used a slightly different method here as well.

One of the things that concerns me is that I am sort of following along with some "before and after" pics from different lenses. The process that Jim linked to does involve several precision steps with tools I do not have.

I feel bad having started this thread and soliciting people's time etc. But at this fork in the road I am now wondering if all this is worth it for this PARTICULAR lens? It does not seem that anyone has photo samples taken with the Rokkor 21/2.8 mounted on a 5D body to convince me one way or the other?

Edited on Nov 15, 2008 at 03:39 AM · View previous versions

Nov 15, 2008 at 03:06 AM

PhotoMaximum
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p.4 #4 · New (used) Rokkor 21mm/2.8

Well, I have decided to do the smart thing: stop thinking about it and pour myself a nice tall cold glass of Rogue Dead Guy Ale...

Fresh eyes and brain cells in the morning and all that jazz...

Max

Nov 15, 2008 at 03:34 AM

cogitech
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p.4 #5 · New (used) Rokkor 21mm/2.8

Cheers!

(A nice glass of Portuguese Red)

...and some port, and...

Nov 15, 2008 at 03:38 AM

PhotoMaximum
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p.4 #6 · New (used) Rokkor 21mm/2.8

cogitech wrote:
Cheers!

(A nice glass of Portuguese Red)

...and some port, and...

You're my kind of guy...

I tried a Portuguese red the other week and really liked it. I love red wine but my experience/knowledge with Portuguese grape juice is very poor...

Cheers,

Max

PS: it turns out I know two people with a mill/lathe so there might be options for me yet. But enough for one day...

Nov 15, 2008 at 03:43 AM

cogitech
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p.4 #7 · New (used) Rokkor 21mm/2.8

I find the most amazing values in Spanish and Portuguese reds. Wonderful, rich wines with more history and a much lower price than Chile, for instance.

Tempranillo (Spain) is by far my favourite grape of all time. The Portuguese call it Aragonez, and they do wonderful things with it as well. I had a $45 bottle of Portuguese 100% Aragonez that could easily compete with the likes of Antinori super-Tuscans, Bordeaux, etc.

Yeh, enough for now. Maybe one more splash of port...

Nov 15, 2008 at 03:56 AM

JimBuchanan
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p.4 #8 · New (used) Rokkor 21mm/2.8

PhotoMaximum wrote:
It does not seem that anyone has photo samples taken with the Rokkor 21/2.8 mounted on a 5D body to convince me one way or the other?

And, therein lies the problem. With an apparent impossible register difference between Minolta and Canon, these have been uncharted waters, until now.

For example, I have, what I think is a great 2nd alternate to the Leica 28 Elmarit in the "plain" Minolta 28/2.0 floating element lens. We have been talking about Olympus for years using adapters, but who knew about Minolta?

As a general statement, I don't see much lateral CA at all in the Minolta wides. Can't speak for overall sharpness, but the Minolta buy-in to challenge the ultimate 21mm Zeiss is 10%, and maybe 20% for the Oly 21?...

Take some film chromes with the lens to help decide.

Nov 15, 2008 at 04:46 AM

Ed Sawyer
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p.4 #9 · New (used) Rokkor 21mm/2.8

Jim, the radial ring will clear the eos flange, just barely. it takes a tiny bit of sanding the inside of it to get it to clear.

on mine I attached the eos flange/bayonet with the original screws, into the minolta flange, which I machined down and nested inside the M42 threaded area (after hogging out the threaded area, and joining them with JBWeld).

I did the 35/1.8 conversions w/o a lathe. Just a dremel and a belt sander.

-Ed

Nov 15, 2008 at 04:58 AM

Ed Sawyer
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p.4 #10 · New (used) Rokkor 21mm/2.8

Max, you don't *need* a lathe for this conversion, but it wouldn't hurt. I do a method similar to both Dimka and jim. I use the original minolta bayonet, epoxied into the inside of the M42 adapter. I hog out the inside of the M42 with a carbide mill in a dremel. It doesnt' have to be perfectly precise, you can align it later when you epoxy it together. Then, I use the same tool or a belt sander to take off the ears on the minolta bayonet. Epoxy the 2 together precisely so they are concentric and even (level) at the mounting area.

Yes, the green area in your pic gets milled/sanded down to remove the ridge and another .5mm or so off of it. (more if you want) There's a fair bit of material there so it's ok to go at it. Then, the M42 flange/adapter and minolta flange/bayonet sandwich gets bolted back on , using original holes and screws. Then, minor clearnancing on the inside of the radial trim ring to allow it to clear the EOS mount. that then gets attached (after reattaching mount/apeture piece to lens body). radial trim ring goes on last. machine little slot in radial ring for EOS camera lens release pin. (where the hole would be in the M42 adapter, which of course has no flange anymore since we took that off, using dremel and belt sander or lathe/mill).

A nice caliper is handy for measuring and aligning stuff.

I think this Rokkor 21 has a chance to hold it's own against the Oly 21/2. I havent' posted it yet but I have the results from the MP test of the Rokkor 21. It spanks the Oly (hard!) in contrast, from wide open all the way down to f/16-22, especially in the corners. The Sharpness is higher than the Oly initially (2 vs 2.8), the Oly gets sharper between 5.6-8, but the Rokkor is sharper before and after that as I recall. I'll try to post that test early next week.

Whether it can dethrone the beast of a distagon - well, I wouldn't count on it. But, at 1/10 the cost, hellyeah I'd say it's worth a try. Would be worth stacking it up against the canon Zooms (16-35, 17-40) where I bet it would really shine pretty decently.

btw, the nice thing about converting this lens is that you don't have to muck around with the lens itself much. most all the work is done on the apeture/mount piece, so lower risk vs. say the 58 1.2.

you need to convert this or pay Jim to do it! ;-)

Since my plate is clear now of the vivitar 28 series 1, I guess I have to start on this Rokkor 21 asap.

-Ed

Nov 15, 2008 at 05:12 AM

JimBuchanan
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p.4 #11 · New (used) Rokkor 21mm/2.8

cogitech wrote:
Seriously, Jim. The CZ21 is just out of this world. Anyone and everyone who has owned or still owns one will tell you.

Think of the sharpest normal or short tele that you can imagine (85L at f4 for instance). The CZ21 is like that from corner to corner at f5.6 only with better microcontrast and huge amounts of 3D effect. It made me shiver the first time I saw the files from it.

Never gone that wide yet, but I had the same response to the Leica 28mm Elmarit.

Nov 15, 2008 at 05:26 AM

PhotoMaximum
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p.4 #12 · New (used) Rokkor 21mm/2.8

OK, I am working on a really nice Elle Columbia Valley Syrah...

Had to take a peak at this thread. Interesting...

Again, thanks to all for their input! I really mean this...

Before it got dark I held the lens with all the wobbly rear end bits against the M42 mounted converter on my 5D. At this stage it does not come close to focussing at infinity. But the close distance views I am getting tells me that this lens could really be something "special"...

Max

Nov 15, 2008 at 05:26 AM

PhotoMaximum
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p.4 #13 · New (used) Rokkor 21mm/2.8

Ok Boys,

I think I am making some progress...

I looked at the on line stuff and Ed's (and others) suggestion of using the Minolta lens mount ring inside the M42 adapter. This allows the four Minolta mounting screws to secure the lens mount. I used a Dremel to grind off the bayonet tabs on the Minolta mount. I also ground off the unwanted flange on the M42 adapter and widened the hole.

I then thought about how much work it would take to accurately grind off enough material to insert the Minonlta lens mount ring inside the M42. I then took off to the local boat yards just below the hill where I live. A lot of the Alaska fishing fleet docks in Ballard. After a couple of "where can I find a machine shop" queries I found a boat place with a very cool guy who had a big old school lathe built in the 1930's. He dropped everything and machined the opening of the M42 to perfectly have the Minolta lens mount ring drop into the center, perfectly flush with the rear ridge. The Minolta mount surface is flush with the M42 but the ridge prevents it from dropping further in. Once I have the little ridge shaved off the aperture ring I should be in the ball park for success. The machine guy offered to tack weld the two rings together (instead of epoxy etc) once I have lined them up correctly.

Here is shot of the Minolta lens mount ring sitting inside the M42 adapter. The fours holes will then line up with the screws that get inserted through the back of the aperture ring...

This image is copyrighted by the owner

Nov 17, 2008 at 11:13 PM

Dim.ka_
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p.4 #14 · New (used) Rokkor 21mm/2.8

Max, cool - another smart idea - but do not forget to place this minolta insert inside m42 adapter in right position, so that eos part of the adapter would be in right place.

Nov 18, 2008 at 12:08 AM

PhotoMaximum
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p.4 #15 · New (used) Rokkor 21mm/2.8

I am getting there... slowly...

Sanding some of the back of the aperture ring to get infinity focus...

Nov 18, 2008 at 12:28 AM

rgallie
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p.4 #16 · New (used) Rokkor 21mm/2.8

Looks like you are making progress Max! I was going to post how to do this conversion without a lathe, but several people figured it out. A Dremel works wonders.

From the picture below of the M42 adapter with the Minolta mount inside it - it looks like you did not take off the needed .5mm from the bottom of the M42 adapter. You can grid away the flange of the adapter, but then you need to sand off or use a lathe to remove .5mm in thickness. It is hard to fix this once you have cut out the inside of the M42 adapter so the two fit together. I would guess this is why you have to sand the aperture ring to get infinity. I made a mess of a few cheapo mounts and lenses before I got it right.

In this style conversion, if the lens focused properly to infinity before conversion, and the conversion was done perfectly, theoretically the lens would be at infinity. Unfortunately it never works out the way, even with a lathe. But I have found it only takes a small adjustment of the lens' infinity setting to get it right. It should not be necessary to modify any of the rest of the lens.

On attaching the two mounts together, I was originally using Superglue and making cutouts for the screws so I could enter the rear of the lens if needed. Jim Buchanan had the excellent idea to use set screws. Both involve some extra work, cutouts for the screws or set screw holes and threading.

On my next conversion I think I will try using a glue that is not permanent so I can force off the Canon mount and then get to the screws for the Minolta mount. I already forced off a mount that was held with Superglue, but it is hard and leaves marks. I need a glue that is strong but still allow the mount to be pried off with effort. There will need to be some testing.

I am interested in the image quality results of the 21mm when you are done...

Rodney

PhotoMaximum wrote:
Ok Boys,

I think I am making some progress...

I looked at the on line stuff and Ed's (and others) suggestion of using the Minolta lens mount ring inside the M42 adapter. This allows the four Minolta mounting screws to secure the lens mount. I used a Dremel to grind off the bayonet tabs on the Minolta mount. I also ground off the unwanted flange on the M42 adapter and widened the hole.

I then thought about how much work it would take to accurately grind off enough material to insert the Minonlta lens mount ring inside the M42. I then took off to the local boat yards just below the hill where I live. A lot of the Alaska fishing fleet docks in Ballard. After a couple of "where can I find a machine shop" queries I found a boat place with a very cool guy who had a big old school lathe built in the 1930's. He dropped everything and machined the opening of the M42 to perfectly have the Minolta lens mount ring drop into the center, perfectly flush with the rear ridge. The Minolta mount surface is flush with the M42 but the ridge prevents it from dropping further in. Once I have the little ridge shaved off the aperture ring I should be in the ball park for success. The machine guy offered to tack weld the two rings together (instead of epoxy etc) once I have lined them up correctly.

Here is shot of the Minolta lens mount ring sitting inside the M42 adapter. The fours holes will then line up with the screws that get inserted through the back of the aperture ring...

This image is copyrighted by the owner

Nov 18, 2008 at 01:18 AM

Tariq Gibran
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p.4 #17 · New (used) Rokkor 21mm/2.8

Well, I am really curious to see how this lens performs. I have read that it is second only to the CZ 21 and if this proves true, I will pick one up for my a900 and adapt it (which should be much easier than what you guys are going through right now). The Olympus is just not an option for the Sony, unfortunately, and I'm very hesitant to tear into a CZ21 given what they go for.

Ed, I would love to see that Modern Photography test.

Nov 18, 2008 at 01:23 AM

cogitech
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p.4 #18 · New (used) Rokkor 21mm/2.8

Tariq Gibran wrote:

Ed, I would love to see that Modern Photography test.

Me too

Nov 18, 2008 at 01:25 AM

Ed Sawyer
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p.4 #19 · New (used) Rokkor 21mm/2.8

I'll try to post it tomorrow. It's mainly numbers like the rest, but at least can be compared to the Oly numbers.

Max you are making headway. the hogging out and fitting of the two rings together is the hard part.

Rodney, you cant' take the .5mm from the M42 flange, it has to come off the lens aperture piece in this case, I think. If you take it off the flange, the bayonet (eos) will too shallow to seat on the camera I'd think.

in my conversions, I remove the flange on the M42 and bring it down to flush so it adds no depth to the whole package. then I take the .5mm off the backside of the apeture piece, where the original minolta bayonet screws on. I think that's the only way to do it, at least or so it seemed to me when I was doing the 35 1.8s.

-Ed

Nov 18, 2008 at 01:50 AM

Tariq Gibran
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p.4 #20 · New (used) Rokkor 21mm/2.8

Hey Ed, I think I found that test report here:

http://photo.net/photodb/photo?photo_id=1108494

Nov 18, 2008 at 01:53 AM

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