It is the edges that distort and cause issues. So stopping down gives
pictures through the center of the lenses.
When I was an AFRS photographer this was a constant lesson. More light
more F-stop and finer quality of picture.
Remember the Christmas pictures in dim light - the grain is high.
A flash cured that. Years of design brought out the magic cube. :-)
When I use a demagnification on my telescope that dumps F10 to F5 I get
edge effects. However since I get 4x light - when taking deep sky photos
one needs all the light possible. We mask off the outside ring and often
just make a square or rectangle as a resultant.
Does the Nikon 6.1 NPx use Nikon F lenses ? That has been one of the great
mysteries and fallouts away from Nikon when they junked our collections
of fine lenses and lost customers all over the world.
Martin
aydin wrote:
> I would think that a macro lens closed down to f45 would create a lot of
> diffraction effects.
>
> Aydin
> snailstales.blogspot.com
>
> On Tue, 25 Nov 2008 10:05:28 -0500, Paul Callomon <[log in to unmask]> wrote:
>
>
>> My ten cents:
>>
>> I have been able to get fairly good photographs by using a Wild
>> microscope (either an M5 or an M6) with the optional diaphragm section.
>> The latter can be bought separately, and adds a diaphragm to the column
>> (both sides). If you focus with it open and then shut it down to about
>> 2.5, you get the same depth of field as a macro lens at f32. The camera
>> is a Nikon digital SLR (6.1 MPx), attached to one of the eyepieces using
>> an adaptor purchased from Edmund Optical in New Jersey. This compensates
>> for eyepiece magnification, and has a standard Leica screw mount that
>> can be customized for any camera using adaptor rings.
>> Lighting can be by ringlight, light pipes or by a regular strobe on one
>> side of the microscope with a handheld mirror on the other to vary
>> shadowing.
>> The only problem with this setup, apart from the cost of the eyepiece
>> adaptor, is a certain amount of purple/yellow halation on edges; this is
>> partly because the light path is going through a prism, and partly
>> because each pixel is approaching the size of the optical Circle of
>> Interference. A finer CCD, like a 10 MPx or so, might improve things. On
>> the other hand, if you already own or have access to an M5 or M6, this
>> is a relatively cheap way to get good micro pictures.
>>
>> I recently obtained a rare Mk1 Medi-nikkor lens from about 1975 - 3 x
>> macro, built-in strobe and a diaphragm that goes to f45! It's fabulous,
>> and gives great color pictures of things down to about 0.5 mm diameter.
>> I've been using it for protoconch and periostracum pictures, with good
>> results.
>>
>> Regards,
>>
>>
>>
>> Paul Callomon
>> Collections Manager
>> Malacology, Invertebrate Paleontology and General Invertebrates
>> Department of Malacology
>> Academy of Natural Sciences
>> 1900 Parkway, Philadelphia PA 19103-1195, USA
>> Tel 215-405-5096
>> Fax 215-299-1170
>> Secretary, American Malacological Society
>> On the web at www.malacological.org
>>
>>
>>>>> Marcus Coltro <[log in to unmask]> 11/25/2008 7:42 AM >>>
>>>>>
>> No, it is not for sale here, only in USA, UK and Japan... and it is
>> "kinda" heavy to carry around,
>> 63 kilos! (140 pounds)
>>
>> Anyway, I would like to hear if these others produce good quality
>> pictures. It is hard to get decent
>> depth of field using regular microscopes - even with the software as
>> there is not much space for
>> take different levels of focus
>>
>> Marcus
>>
>> ________________________________________
>> De: Conchologists List [mailto:[log in to unmask]] Em nome de
>> Wiggers
>> Enviada em: terça-feira, 25 de novembro de 2008 10:08
>> Para: [log in to unmask]
>> Assunto: Re: [CONCH-L] Digital Microscope
>>
>> Uau! I liked those "toys"! Unfortunately it is not possible to find
>> those here in Brazil (is it
>> Marcus???).
>> Hope Santa brings me one for Christmas this year... :)
>>
>> Regards
>> Fabio W.
>>
>>
>> --- Em seg, 24/11/08, Eddy WILMET <[log in to unmask]> escreveu:
>> De: Eddy WILMET <[log in to unmask]>
>> Assunto: Re: [CONCH-L] Digital Microscope
>> Para: [log in to unmask]
>> Data: Segunda-feira, 24 de Novembro de 2008, 22:54
>> Hi Bill in fact this is the one I was talking about (paste this
>> commandline):
>>
>> http://www.virtuavia.eu/shop/index.php?
>> target=products&product_id=29887&sl=EN
>>
>> Regards,
>>
>> Eddy
>> WILMET
>> www.euromurex.be
>>
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--
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/
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