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  • Archphoto
    replied
    Re: smaller baffle plates?

    I measured the rear of the 11-22mm and came to 27mm, so the should be some play.
    On the other hand the Olympus Digital lenses have a better control of how the light strikes the sensor: straight on instead of under an angle.
    I just have my old 1.8/50mm left.....

    But with some black cardboard you can draw a number of circles on it and start with the smallest one and use the hole that gives you not dark corners.
    That should be the propper baffle, purely theoreticly ofcourse.

    Time to experiment !

    Peter

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  • jimindenver
    replied
    Re: smaller baffle plates?

    I'm going to have to give this a try with the OM 20mm.

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  • Olyglass
    replied
    Re: smaller baffle plates?

    I just read this thread with great interest. I was just about to make a baffle for my Minolta-4/3s adapter. I wanted to double check what the diameter of the center hole should be. I read both 17mm, and 18mm in this thread. I grabbed a 14-54mm lens, and the rear element measures 18mm from edges of the glass.

    I then started wondering if all the ZD lenses have the same size baffles and rear elements. They do not. The faster the lens, the larger the rear element, and also the baffle. The 35-100mm baffle has a giant opening in the baffle compared to the slower lenses. See attached pic.

    So now I'm wondering if an 18mm hole in my homemade baffle is not a good idea. Since the 35-100mm is f2, a legacy lens like a 50mm f1.2 or f1.4 seems like it should have AT LEAST the same size hole in the baffle as the 35-100mm lens.

    What do you guys think?

    Marc
    Attached Files

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  • AndyElliott
    replied
    Re: smaller baffle plates?

    Originally posted by mike_j View Post
    I'm no optics expert but I should think that a rough edge to the aperture of the baffle might cause small scale distortion/diffusion which would degrade the image slightly. I haven't tried making a baffle yet so this is only conjecture.

    I think I will laser cut some 'perfect' 17mm dia holes in some thin acrylic and run some comparisons. Blacked shim steel would be better but I can't get that laser cut (at least not free).
    True - more a proof of principle rather than a finished article - definitely better even with my half-arsed job! The hole diameter is about 18mm - so beyond area where it might interfere, but it should still cut down reflections. Given the CCD is shiny (more so than film), it will be impossible to completely cut down all returned light. It is interesting that lens sold by, say, Nikon and Canon for APS-C/DX and full-frame should also benefit from the baffle on the smaller sensor - as should four-thirds Sigma DG (i.e. derived from full-frame) unlike the DC lenses.

    Andy

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  • Archphoto
    replied
    Re: smaller baffle plates?

    Actualy I was thinking about this a couple of days ago.
    I was thinking of a bafle plate with a rectangular hole in it, made of thin blacked copper plate and mount that on the rear of the OM<>4/3 adapter.

    Maybe a rectangular hole will work even better because you block off more unwanted light. Have to try that......

    Peter

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  • mike_j
    replied
    Re: smaller baffle plates?

    I'm no optics expert but I should think that a rough edge to the aperture of the baffle might cause small scale distortion/diffusion which would degrade the image slightly. I haven't tried making a baffle yet so this is only conjecture.

    I think I will laser cut some 'perfect' 17mm dia holes in some thin acrylic and run some comparisons. Blacked shim steel would be better but I can't get that laser cut (at least not free).

    Leave a comment:


  • AndyElliott
    replied
    Re: smaller baffle plates?

    Originally posted by MikkoH View Post
    The 50 f1.4 work unbelievably great! The baffle plate really does make a clear difference

    heres a
    pic of the baffle plate
    I can second that - here's what I did just now - here on a MF-1 copy with the dandelion chip (looks crap - but the result is excellent). Noticeably, wide open on a 50mm f1.4, the result is sharper because of less glare.

    Just a bit of card glued into the mf-1, 1mm recessed from the back of the adapter.

    Andy
    Last edited by AndyElliott; 9th May 2009, 01:59 PM.

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  • Kuifje
    replied
    Re: smaller baffle plates?

    Now what if someone would start producing an OMZ to mFT adaptor but then with:

    a) a micro adjustable lenght so that you can easily fine tune infinity setting on legacy glass.

    b) an adjustable diafram, or replaceable orifices, to "baffle" or catch all light not intended for the sensor.

    As it is fully manual it can't be that hard to make .. and you would not need to modify lenses to reach optimum contrast.

    Hmm .. I would be interested..

    Martin

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  • MikkoH
    replied
    Re: smaller baffle plates?

    Originally posted by Kuifje View Post
    rjstaunt, thanks

    MikkoH, did you manage to get the 50 f1.4 working?
    The 50 f1.4 work unbelievably great! The baffle plate really does make a clear difference

    heres a
    pic of the baffle plate

    Leave a comment:


  • HughofBardfield
    replied
    Re: smaller baffle plates?

    This is very interesting. I wonder if it would be possible to fit something semi-permanently in the MF-1 adaptor to achieve the same effect? (Obviously, the Hexanons are a different case - I have a 40mm f1.8 in the process of conversion at the moment, and will try a baffle on that too)

    Leave a comment:


  • Kuifje
    replied
    Re: smaller baffle plates?

    rjstaunt, thanks

    MikkoH, did you manage to get the 50 f1.4 working?

    Leave a comment:


  • rjstaunt
    replied
    Re: smaller baffle plates?

    http://gfsnt.no/hexanon/ this is where I went as a reference when converting my hexanons.

    i didn't make any comparison shots but i can tell the difference through the viewfinder. without the baffle, there is a slight luminous glow to everything (that looks cool as an effect) and little bit of flare/glare... with baffle everything is darker (more realistic) and very contrasty, without flare/glare.

    i used scotch tape to attach my baffles around the sides of the piece with all the glass in it, so the baffle moves with the glass as you focus.

    Leave a comment:


  • Kuifje
    replied
    Re: smaller baffle plates?

    Any "how to's"? Do you open up the lens or attach to the rear lens element (mount)?

    Would be interested to see some comparisson shots

    Leave a comment:


  • rjstaunt
    replied
    Re: smaller baffle plates?

    i just noticed that a dime is exactly 17mm across! i should have thought of that in the first place....

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  • rjstaunt
    replied
    Re: smaller baffle plates?

    I have a Konica Hexanon AR 57 mm f/1.4 and 40 mm f/1.8 that I have rigged up to the e-510... I put a baffle on the 1.4 but haven't gotten to the 1.8 yet. My baffle is made out of a gasket material (cardboard-like) that i colored in with a black sharpie marker. It's a pretty hack job---not even circular. i wonder if the details matter... should I make a better one? I tried to make the hole roughly the same diameter as the back element of the 4/3 kit lenses.

    btw i love the hexanons. its so cool that you don't even need to use an adapter to use them with the e-510, they're cheap, and very good image quality.

    Leave a comment:

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