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Archive 2017 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

pasblues
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p.1 #1 · p.1 #1 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

I have a 7.5mm Minolta fisheye that adapts to my FujiX-T2 with a K&F adapter.

But I want the full circular so I have a Sony a7r and got a K&F adapter for Minolta to NEX.

This fisheye captures aren't in focus anywhere on the Sony frame - so something's completely off even though the adapter fits perfectly on both lens and body.

There's no focus ring on the fisheye that I can find because, presumably, the lens is in focus from a foot and a half on. It's fine on my Fuji X but it crops and doesn't give a full circular view. But the lens yields perfectly focused images.

I'm open to getting a different adapter - like Novaflex - if that would solve the problem but I'd rather find out what the problem might be first before I go throwing another adapter at this issue.

Peggy

Sep 05, 2017 at 12:41 PM

Slalom
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p.1 #2 · p.1 #2 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

Have you tried the A7r and adapter with other lenses? That would give you a chance to try focusing. The other thing to try is zooming in for focus confidence.

Sep 05, 2017 at 03:47 PM

pasblues
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p.1 #3 · p.1 #3 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

I'm sorry, I wasn't complete in my post. Yes, I can use the K&F adapter on the Sony with other Minolta MC lenses - the 85 f1.7, a 100mm f4 macro/extension tube setup, and the 16mm f2.8 fisheye - and they are all fine with the Sony. These lenses have focusing capabilities and I can focus them manually and accurately. Now, I say that...and I'm not an expert with adapters. There are strange things that happen with adapting lenses that I have yet to examine closely and explain in some way.

Anyway, It is only the 7.5mm fisheye that is not focusing at all on the Sony. Focusing with this lens means, pretty much, picking your composition and positioning yourself at a distance from your close subject that meets the minimum distance in accordance with your aperture, like 3 feet or 1.5 feet - then everything after that is in focus.

But NOTHING is in focus, even at f22 - when the lens is mounted to the Sony with the K&F.

With a K&F adapter for MC to FX on the Fuji, the 7.5mm Minolta works perfectly fine.

Today, I ordered two other adapters to see if the lens will like a different adapter. There's nothing wrong with the lens. There's nothing wrong with the K&F adapter for other Minolta MC lenses and the Sony.

But, wouldn't it be a curiosity if this one lens just didn't like the K&F adapter for the Sony - but some other brand of adapter did work? We shall find out in a couple of days.

In the meantime, if there are any adapter experts out there who have experienced situations where different lenses and body combinations required different brands of adapters or other oddity situations, I'd love to hear from you. I'm new to the adapter world and there aren't very many experts out there in internet land.

Peggy

Sep 05, 2017 at 08:54 PM

mcbroomf
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p.1 #4 · p.1 #4 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

When you put the 85mm and 16mm fish on the camera with the adapter where do the lens scales end up when you're focusing on infinity, ie are they short of the hard stops? It's not uncommon for adapters to be too thin, either by design or due to manufacturing tolerances. Your other Minolta lenses are able to compensate with the focus helicoid but not the 7.5 fish. However if these lenses are at infinity when they are at the hard stop then there's a problem with the 7.5mm lens, although if it's OK on the Fuji it seems unlikely. If the adapter is thin then either you need to find an adapter which is the exact thickness required to give infinity at the hard stops of your other lenses, and this will make the 7.5mm lens work properly, or shim the adapter to make it thicker.

PS. According to the Rokkor files the lens is fixed focus at 1.2 meters
http://www.rokkorfiles.com/7-5mm.htm

Mike

Sep 06, 2017 at 02:23 AM

pasblues
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p.1 #5 · p.1 #5 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

Sounds about right, Mike. I ordered two other adapters - a Fotodiox and a Novaflex, both which are supposed to be set to infinity (the Fotodiox advertising that it is guaranteed infinity).

Just follow the logic that the lens works on the Fuji and not the Sony, tells me there's nothing wrong with the lens (and I paid a premium for it because it is "as new").

So, the only thing left it could be is the infinity issue - which either the other adapters or shims will fix. When it is focused, it's extremely sharp.

I should note that I did review that article you just posted - along with a lot of other research prior to purchasing this lens. Interestingly, my lens is the MC model, not the MD model. And it came in the box with the DOF tables and a little instruction sheet. At f4 (wide open), everything 15" forward should be in focus, with that number getting smaller with smaller aperture settings (down to 6.25" at f22). I don't know that there were any significant differences between the MC and MD models.

Peggy

Sep 06, 2017 at 08:44 AM

pasblues
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p.1 #6 · p.1 #6 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

I don't know how to make shims. Anybody? Sorry if this is discussed elsewhere, I'll delete my question.

Sep 06, 2017 at 09:02 AM

sebboh
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p.1 #7 · p.1 #7 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

pasblues wrote:
I don't know how to make shims. Anybody? Sorry if this is discussed elsewhere, I'll delete my question.

you can use something like this.

or you can cut up tinfoil and flatten it.

Sep 06, 2017 at 10:30 AM

mcbroomf
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p.1 #8 · p.1 #8 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

This might give you an idea what you'd be getting into if the new adapters are also thin and you decide to try shimming. It's not a dumb adapter but the principle is the same. Just make sure you have the right type of screwdriver to avoid stripping the heads.
https://www.fredmiranda.com/forum/topic/1415739/2&year=2016#13444891

Sep 06, 2017 at 11:02 AM

pasblues
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p.1 #9 · p.1 #9 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

I have contacted someone who can make a focusing helicoid if it comes down to it also. The lens is not inexpensive enough to take it apart. It's rare and too valuable.

However, I am going to study these offerings you guys have sent should I embark on experimenting with less expensive lenses. Thank you!

Sep 06, 2017 at 09:12 PM

pasblues
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p.1 #10 · p.1 #10 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

Man, you guys know how to do some cool stuff.

Sep 06, 2017 at 09:19 PM

mcbroomf
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p.1 #11 · p.1 #11 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

pasblues wrote:
I have contacted someone who can make a focusing helicoid if it comes down to it also ...

They already exist!
http://www.ebay.com/itm/Kipon-Adapter-with-Focus-Helicoid-for-Minolta-MD-Mount-Lens-to-Sony-E-NEX-A7R2-/272824780274?hash=item3f859fc5f2:g:SfcAAOSwNRdX8hQt

There might be a cheaper one (I have a couple of makes), let me look around...

Here is a much cheaper one
http://www.ebay.com/itm/Minolta-MD-lens-to-Sony-E-mount-adapter-NEX-macro-focusing-helicoid-A6000-A5000-/152653684858?hash=item238ade607a:g:npkAAOSwnbZYIC5E

Edited on Sep 07, 2017 at 03:42 AM · View previous versions

Sep 07, 2017 at 03:23 AM

mcbroomf
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p.1 #12 · p.1 #12 · Need adapter advice for Minolta 7.5mm fisheye to Sony a7r

You could also combine a Minolta - Leica M adapter then a Leica M - Sony close focus adapter (has a short helicoid). Both of these adapters are relatively cheap and some have an adjustable infinity lock that you may be able to tweak to the "right" infinity for the fish

Leica close focus adapter
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xleica+m+to+sony+focus+adapter.TRS0&_nkw=leica+m+to+sony+focus+adapter&_sacat=0

Minolta - Leica adapter
https://www.ebay.com/sch/i.html?_odkw=leica+m+to+sony+focus+adapter&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xminolta+lens+to+leica+m+adapter.TRS0&_nkw=minolta+lens+to+leica+m+adapter&_sacat=0

Sep 07, 2017 at 03:31 AM


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