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Thread: Dallmeyer 25mm f0.98

  1. #1

    Dallmeyer 25mm f0.98

    Hello everyone,first post..I have an old Dallmeyer Ultrac 25mm F0.98 in C mount that I was hoping to use on my Oly. E-P1.I got an adapter from e-bay and have mounted the lens but the results are strange.The pictures a circular and I can't focus to infinity.Can anyone advise me? Is it the adapter I'm using? It's a thin one and sits flush against the body of the camera.I can't find much info. online,mostly Japanese Forums.I think the lens is pretty rare but if it will work better on another camera I might just sell it 'cause my eyesight 'aint too good and I love autofocus these days.I've attached a picture,but I don't know if it will upload.Thanks.

  2. #2
    Member sangio's Avatar
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    Feb 2009
    London, Ontario, Canada
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    Re: Dallmeyer 25mm f0.98

    Hello and welcome

    I'm not familiar with that particular lens, but many c-mount lenses won't seat properly in the adapters and require slight machining to make them fit. I had to do that with a Cosmicar 12.5 mm lens.
    Here's a link to a blog that describes how to do it in great detail. I used a metal file.

    The roundish image circle is also quite common. A lot of these lens were designed for film sizes with a diameters smaller than the m4/3 sensor.

    There are a lot of older conversations in this site with useful information, just search for

    best regards

  3. #3

    Re: Dallmeyer 25mm f0.98

    Thanks Santo,Interersting stuff..Maybe keep the lens for a while 'til I know more about 'em.
    I'm used to using old MF lenses on my Oly.E-330 but this new Micro 4/3 rds mount is all new terriority to me.I have some nice old glass in Canon FD & Minolta MD mounts and maybe will check them out first.My previous attempts at repair/modification have not gone well on account of my big hands/ short fuse!!..Cheers, Liam.

  4. #4
    Join Date
    Mar 2010
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    Re: Dallmeyer 25mm f0.98

    Welcome Liam!

    That should be a cracking lens. Nikon may be coming out with a 16mm lens compatible mirror less camera.

    There should be less vignetting as 25mm seems to be a threshold for m4/3 sensor coverage. You should get better results perhaps with a different adapter? Such a fast lens will be large of body. The lens itself may have a part that is removable which might mean that you do not need to file it down. The trick would be to find a c mount that could be glued to the lens and then inserted into the adapter you have?

    Have fun and post lots of pics?

  5. #5

    Re: Dallmeyer 25mm f0.98

    Thanks Pat.It as a nice old lens and what you say about Nikon is very interesting.Don't really fancy taking a file to the lens and might just put it aside to see what pops up next.Interesting times alright.Wonder what Canon will do?The lens is nice and I can focus fine @ around 1-2 feet.Plus it seems to scoop in light to the sensor,but the way it is now it's only good indoors and I like to shoot in the street.Anyway,after using MF lenses so long it's nice to have autofocus again with the little Zuiko pancake that came with the E-p1.Might just get an FD-M4/3 adapter,I have a fast (1.2) Canon prime that I would like to see what it shoots like.Should be a good twilight lens although it will be 100 mm and huge on the little Oly as the adapters for FD look quiet chunky.Thanks again guys,and sorry if I'm asking dumb**s questions,was a 4/3 rds shooter until last week and didn't look too closely at the new kids on the block in case I had a GAS attack!.Love the 'Pen,great camera.An OM1 for the times.Hope Mr. Maitani lived to see it.

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