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Hi,

Just had an idea. Why hasn't anyone come up with
a teleconverter which reduces a full frame image
down to a 1.5 or 1.6 crop. Sort of like what those
older Nikon DSLRs did in the body.

Say we had a 0.7x (1/1.4x) converter. If the image
reduced by 1.4 times, then you would gain 1 whole
stop as well since we are concentrating it on
half the area.

Wouldn't this work theoretically? if we had
perfect glass that didnt give distortion or
chormatic abberations, this would work, would
it not? Could we keep infinity focus on
something like this?

Just my thoughts anyway. If it could be built
at the same price as the other OEM Teleconverters
(or even twice, it better have decent glass in it),
it would still beats paying for a current full
frame DSLR.

Vin.
--
Vin
Melbourne, Australia
Remove no and spam from both sides of the @ sign email address to reply

"Vin" <> wrote in message
news:9sfnnb.8q2.ln@192.168.11.2...
> Hi,
>
> Just had an idea. Why hasn't anyone come up with
> a teleconverter which reduces a full frame image
> down to a 1.5 or 1.6 crop. Sort of like what those
> older Nikon DSLRs did in the body.

That would be an anti-teleconverter.


>
> Say we had a 0.7x (1/1.4x) converter. If the image
> reduced by 1.4 times, then you would gain 1 whole
> stop as well since we are concentrating it on
> half the area.
>
> Wouldn't this work theoretically? if we had
> perfect glass that didnt give distortion or
> chormatic abberations, this would work, would
> it not? Could we keep infinity focus on
> something like this?

I shouldn't think keeping infinity focus would be a problem for an
anti-teleconverter, since teleconverters do it without difficulty.

Your idea is certainly intriguing. There may be something wrong with it, but
I can't think of what it might be. Since a 1.4x converter loses you a stop,
it does seem reasonable that a 0.7x converter would gain you a stop, and
doing away with that pesky multiplier (or most of it) would make the thing
worthwhile anyway.

Neil


>
> Just my thoughts anyway. If it could be built
> at the same price as the other OEM Teleconverters
> (or even twice, it better have decent glass in it),
> it would still beats paying for a current full
> frame DSLR.
>
> Vin.
> --
> Vin
> Melbourne, Australia
> Remove no and spam from both sides of the @ sign email address to reply

"Vin" <> wrote in message
news:9sfnnb.8q2.ln@192.168.11.2...
> Hi,
>
> Just had an idea. Why hasn't anyone come up with
> a teleconverter which reduces a full frame image
> down to a 1.5 or 1.6 crop. Sort of like what those
> older Nikon DSLRs did in the body.
>
> Say we had a 0.7x (1/1.4x) converter. If the image
> reduced by 1.4 times, then you would gain 1 whole
> stop as well since we are concentrating it on
> half the area.
>
> Wouldn't this work theoretically? if we had
> perfect glass that didnt give distortion or
> chormatic abberations, this would work, would
> it not? Could we keep infinity focus on
> something like this?
>
> Just my thoughts anyway. If it could be built
> at the same price as the other OEM Teleconverters
> (or even twice, it better have decent glass in it),
> it would still beats paying for a current full
> frame DSLR.

Why not take all the energy and engineering required to produce the item as
you describe it, and instead make lenses that are actually full frame with
sensors smaller than 24 X 36 mm?

"PhotoMan" <> wrote in message
news:dZPnb.62873$. ..
>
> "Vin" <> wrote in message
> news:9sfnnb.8q2.ln@192.168.11.2...
> > Hi,
> >
> > Just had an idea. Why hasn't anyone come up with
> > a teleconverter which reduces a full frame image
> > down to a 1.5 or 1.6 crop. Sort of like what those
> > older Nikon DSLRs did in the body.
> >
> > Say we had a 0.7x (1/1.4x) converter. If the image
> > reduced by 1.4 times, then you would gain 1 whole
> > stop as well since we are concentrating it on
> > half the area.
> >
> > Wouldn't this work theoretically? if we had
> > perfect glass that didnt give distortion or
> > chormatic abberations, this would work, would
> > it not? Could we keep infinity focus on
> > something like this?
> >
> > Just my thoughts anyway. If it could be built
> > at the same price as the other OEM Teleconverters
> > (or even twice, it better have decent glass in it),
> > it would still beats paying for a current full
> > frame DSLR.
>
> Why not take all the energy and engineering required to produce the item
as
> you describe it, and instead make lenses that are actually full frame with
> sensors smaller than 24 X 36 mm?

Great idea, but there are so many different sizes of sensors. The handy
thing about lenses for 35mm cameras is that they all are designed to cover
that 24 x 36 mm, and never any need to redesign 'em for larger or smaller
formats--which would create a manufacturing and marketing nightmare in the
case of digital SLRs, I should think.

Besides, a major attraction to digital SLRs is that they allow the buyer to
use his existing film SLR lenses--not have to buy a whole new set.

I don't see why "all the energy and engineering required" should be so much
anyway, just to design an anti-teleconverter. And it would only have to be
done ONCE, then all existing lenses could be used.

Neil

In message <RoPnb.16720$ >,
"NJH" <> wrote:

>That would be an anti-teleconverter.

Or a tele-inverter.
--

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