From: R. Mark Clayton on

"nospam" <nospam(a)nospam.invalid> wrote in message
news:120820080430304223%nospam(a)nospam.invalid...
> In article <XMmdnYgHDrpo-TzVnZ2dnUVZ8u2dnZ2d(a)bt.com>, R. Mark Clayton
> <nospamclayton(a)btinternet.com> wrote:
>
>> "Mulperi" <juha.heinonen(a)pp2.inet.fi> wrote in message
>> news:zC1ok.275$T16.103(a)read4.inet.fi...
>> > Which one is better. Yes I know that Tamron AF 200-500 F5-6,3 Di LD IF
>> > is
>> > a zoom lens
>>
>> This does not appear to be a full frome lens - this means it won't work
>> on a
>> 35mm film back or Sony's up and coming full frame digital. OTOH this
>> will
>> make the lens lighter - under normal circumstances this would be a very
>> heavy lens.
>
> i don't know where you got the idea that it's not a full frame lens.
> it most definitely is. also, full frame lenses that long won't be any
> lighter than a dx version. it's at the shorter focal lengths where
> cropped image circles make a difference.

Apologies for that - it was the Di - spec says it is equivalent to 750mm on
APS-C frame cameras. (I think the industry needs to sort this out).

It is heavy at 1237g.

>
>> The AF may be poor at 300+ on the zoom.
>>
>> > and SONY 500/8 REFLEX is not but which one gives better photos.
>>
>> This is Minolta's 500mm reflex with a Sony badge. It is designed to work
>> with the Minolta / Sony cameras and will AF properly - useful because
>> things
>> out of focus in a reflex lens appear torroidal. Image quality should be
>> good, since as a mirror lens there are only reflections, so chromatic
>> abberation will not occur.
>>
>> Should work well with a doubler (giving f16 at 1000mm)
>
> ugh.

Because there will be few abberations from the reflex bit.

665g

>
>> PS back in the manual days Minolta did a 250mm reflex. Scarcely any
>> bigger
>> than standard prime lens and very light. Lovely if one didn't want to
>> take
>> a full kit.
>
> actually a number of companies made 300mm f/5.6 mirror lenses. they're
> *really* small considering they're 300mm, and f/5.6 isn't that slow
> (most consumer zooms are f/5.6 at the long end).

Indeed.


From: nospam on
In article <8L6dnTaBiZ0Y5zzVnZ2dneKdnZydnZ2d(a)bt.com>, R. Mark Clayton
<nospamclayton(a)btinternet.com> wrote:
>
> Apologies for that - it was the Di - spec says it is equivalent to 750mm on
> APS-C frame cameras. (I think the industry needs to sort this out).

the only confusing thing is the various nomenclature used by the
different manufacturers. tamron is probably the worst with di
(digitally integrated) for lenses with different coatings and di-ii for
cropped sensor lenses. sigma uses dc and dg, while nikon uses dx.

> It is heavy at 1237g.

yep, it's a big lens. sigma has a number of alternatives, all of which
are heavier. and if you really want extreme, there's the sigma
200-500mm f/2.8, which weights something like 35 pounds. :)

<http://www.sigma-photo.co.jp/english/news/200_500_28.htm>

> >> The AF may be poor at 300+ on the zoom.
> >>
> >> > and SONY 500/8 REFLEX is not but which one gives better photos.
> >>
> >> This is Minolta's 500mm reflex with a Sony badge. It is designed to work
> >> with the Minolta / Sony cameras and will AF properly - useful because
> >> things
> >> out of focus in a reflex lens appear torroidal. Image quality should be
> >> good, since as a mirror lens there are only reflections, so chromatic
> >> abberation will not occur.
> >>
> >> Should work well with a doubler (giving f16 at 1000mm)
> >
> > ugh.
>
> Because there will be few abberations from the reflex bit.

even the best converters have an impact on image quality and
diffraction becomes an issue at f/16. plus, looking through a lens at
f/16 (nevermind trying to focus it) is painful.

> 665g

that's about the only good aspect.
From: Chris Malcolm on
R. Mark Clayton <nospamclayton(a)btinternet.com> wrote:

> PS back in the manual days Minolta did a 250mm reflex. Scarcely any bigger
> than standard prime lens and very light. Lovely if one didn't want to take
> a full kit.

Plus with enough aperture to autofocus without special internal aid,
and a useful telephoto length of 375mm on a 1.5 crop sensor. Shame it
needs a lensed convertor to work on a Sony alpha mount.

--
Chris Malcolm cam(a)infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

From: David Kilpatrick on
Chris Malcolm wrote:
> R. Mark Clayton <nospamclayton(a)btinternet.com> wrote:
>
>> PS back in the manual days Minolta did a 250mm reflex. Scarcely any bigger
>> than standard prime lens and very light. Lovely if one didn't want to take
>> a full kit.
>
> Plus with enough aperture to autofocus without special internal aid,
> and a useful telephoto length of 375mm on a 1.5 crop sensor. Shame it
> needs a lensed convertor to work on a Sony alpha mount.
>


The main problem with the 250mm f5.6 on full frame was very strong
vignetting, which you couldn't do anything about. I had this lens but in
the end, the gain over the 75-200mm conventional zoom or the 200mm f4.5
was not enough to compensate for the restrictions.

However, on APS-C the vignetting would not be an issue and the aperture,
size and length would make it a great design to re-issue in AF form.

David
From: R. Mark Clayton on

"David Kilpatrick" <iconmags3(a)btconnect.com> wrote in message
news:UJGdnX6EGdMpPjzVnZ2dnUVZ8vydnZ2d(a)bt.com...
> Chris Malcolm wrote:
>> R. Mark Clayton <nospamclayton(a)btinternet.com> wrote:
>>
>>> PS back in the manual days Minolta did a 250mm reflex. Scarcely any
>>> bigger than standard prime lens and very light. Lovely if one didn't
>>> want to take a full kit.
>>
>> Plus with enough aperture to autofocus without special internal aid,
>> and a useful telephoto length of 375mm on a 1.5 crop sensor. Shame it
>> needs a lensed convertor to work on a Sony alpha mount.
>>
>
>
> The main problem with the 250mm f5.6 on full frame was very strong
> vignetting, which you couldn't do anything about. I had this lens but in
> the end, the gain over the 75-200mm conventional zoom or the 200mm f4.5
> was not enough to compensate for the restrictions.

I knocked back [various brand] 19-35 zoom lenses until recently after I
realised that the dark corners at short focal lenght were a natural effect
not a defect in the lens*, however why did the [long] lens above suffer from
it - was it because of the way the secondary mirror worked or got in the
way?

>
> However, on APS-C the vignetting would not be an issue and the aperture,
> size and length would make it a great design to re-issue in AF form.

Oh yes.

And a zoomable multiplier?

>
> David



* at 19mm on to 35mm film, about 45degrees in the corner, so (cos 45)**4 =
0.25!


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