Re: [M]: RE: Maks vs Scts
| Subject: | Re: [M]: RE: Maks vs Scts |
| From: | Gene Horr |
| Date: | Wed Nov 12 07:45:33 1997 |
Dear Clive:
>
> The native f/6.3 will deliver a wider unvignetted FOV.
This what I was assumed the original poster was interested
in.
> However, the f/6.3 does have a significantly bigger central
> obstruction, which means lower contrast and physically
> greater light blockage. However, the f/6.3 telecompressor
> when used on an F/10, will also loose some light due to
> reflection at the lens surfaces, so brightness of the two
> systems is comparable.
This is correct up to a point - IMO when using a native f/6.3
system one will be able procuce sharper photographs when using
emulsion. Photographs that I have seen seem to bear this out,
although there are enough other variables (different
photographers, dates, locations, etc) to question any conclusion.
When doing CCD I cant tell any difference. I agree that
theoretically the f/10 with reducer should show more contrast
but I have not been able to tell a difference.
> The biggest problem that the native f/6.3 system has is greater
> off-axis aberrations than what a tele-compressed f/10 system
> shows. Field curvature and coma of the native f/6.3 system is
> *far* worse. Personally, I would much rather put up will some
> vignetting that the telecompressed f/10 system will (sometimes)
> show, rather than the mushy off-axis imaging that the native
> f/6.3 delivers, but thats just my $0.02.
I own the f/10 and so am using second hand info. The photographs
(35 mm) that I have viewed from the f/6.3 do not show any apparent
distortion at all. I can detect distortion when using the focal
reducer. It is possible that the photos I have seen from the native
f/6.3 systems are masked off, but it seems to me that most (if not
all) of the aberrations from the f/6.3 should not fall on the films
exposure area. If this is true than the native f/6.3 would still
be the best choice.
I am not happy with the results of my f/10 with the focal reducer.
I have spoken in depth with only one owner of an f/6.3 and he was
very happy with his results.
Are there any f/6.3 owners out there that could share their
experience?
Gene Horr
c/o dfrancon@swbell.net
>
> The native f/6.3 will deliver a wider unvignetted FOV.
This what I was assumed the original poster was interested
in.
> However, the f/6.3 does have a significantly bigger central
> obstruction, which means lower contrast and physically
> greater light blockage. However, the f/6.3 telecompressor
> when used on an F/10, will also loose some light due to
> reflection at the lens surfaces, so brightness of the two
> systems is comparable.
This is correct up to a point - IMO when using a native f/6.3
system one will be able procuce sharper photographs when using
emulsion. Photographs that I have seen seem to bear this out,
although there are enough other variables (different
photographers, dates, locations, etc) to question any conclusion.
When doing CCD I cant tell any difference. I agree that
theoretically the f/10 with reducer should show more contrast
but I have not been able to tell a difference.
> The biggest problem that the native f/6.3 system has is greater
> off-axis aberrations than what a tele-compressed f/10 system
> shows. Field curvature and coma of the native f/6.3 system is
> *far* worse. Personally, I would much rather put up will some
> vignetting that the telecompressed f/10 system will (sometimes)
> show, rather than the mushy off-axis imaging that the native
> f/6.3 delivers, but thats just my $0.02.
I own the f/10 and so am using second hand info. The photographs
(35 mm) that I have viewed from the f/6.3 do not show any apparent
distortion at all. I can detect distortion when using the focal
reducer. It is possible that the photos I have seen from the native
f/6.3 systems are masked off, but it seems to me that most (if not
all) of the aberrations from the f/6.3 should not fall on the films
exposure area. If this is true than the native f/6.3 would still
be the best choice.
I am not happy with the results of my f/10 with the focal reducer.
I have spoken in depth with only one owner of an f/6.3 and he was
very happy with his results.
Are there any f/6.3 owners out there that could share their
experience?
Gene Horr
c/o dfrancon@swbell.net
