Wildlife photogs need to go beyond camera lenses

Archived from groups: rec.photo.digital.slr-systems (More info?)

I've seen quite a few shots of animals recently where the photogs
coudn't get too close, for various reasons. What struck me was that
although the shots were sharp, they were obviously heavily cropped
because noise was evident in them. Noise in pro DSLRs is "attractive"
in a film-like way, but the cropping still reduces the overall quality
of the image. If a photog is using a 600mm lens with a converter to
get 1200mm, and it's still not enough to avoid heavy cropping, maybe
it's time to get away from long refractive telephotos and into reflex
systems that would allow much greater focal lengths while maintaining
a reasonable focal ratio? The only drawback of course would be the
inability to stop-down and the attendent short depth of field. But,
there are lens systems out there that can provide focal lengths in the
2500mm range with f6.3 focal ratios. No autofocus though.
-Rich

Archived from groups: rec.photo.digital.slr-systems (More info?)

In message <fa47i193dvptd5bcdh2cu612a9psvgin7d@4ax.com>,
Rich <none@none.com> wrote:

>I've seen quite a few shots of animals recently where the photogs
>coudn't get too close, for various reasons. What struck me was that
>although the shots were sharp, they were obviously heavily cropped
>because noise was evident in them. Noise in pro DSLRs is "attractive"
>in a film-like way, but the cropping still reduces the overall quality
>of the image. If a photog is using a 600mm lens with a converter to
>get 1200mm, and it's still not enough to avoid heavy cropping, maybe
>it's time to get away from long refractive telephotos and into reflex
>systems that would allow much greater focal lengths while maintaining
>a reasonable focal ratio? The only drawback of course would be the
>inability to stop-down and the attendent short depth of field. But,
>there are lens systems out there that can provide focal lengths in the
>2500mm range with f6.3 focal ratios. No autofocus though.

Might work for a bird on a wire, or in the sky, but the bokeh would be a
mess for an animal in the brush or in a tree.
--

<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<>
John P Sheehy <JPS@no.komm>
><<> <>>< <>>< ><<> <>>< ><<> ><<> <>><

Archived from groups: rec.photo.digital.slr-systems (More info?)

"Stacey" <fotocord@yahoo.com> wrote in message
news:3oi410F62362U4@individual.net...
> Ed Ruf wrote:
>
> > On Sat, 10 Sep 2005 22:12:52 -0400, in rec.photo.digital.slr-systems
Rich
> >The only drawback of course would be the
> >>inability to stop-down and the attendent short depth of field. But,
> >>there are lens systems out there that can provide focal lengths in the
> >>2500mm range with f6.3 focal ratios. No autofocus though.
> >
> > And the brokeh looks like what?
> >
>
> Ugly beyond words?
>
> I own one mirror lens and it's such a PITA to use and produces such UGLY
> bokeh, the only thing it can even be used for is maybe a bird or something
> in water or in the sky.


Some folks like it, some folks don't.
http://mendosus.com/jpg/gumnuts.jpg
Some folks don't care either way.

This example is a particularly *aggressive* one.

--
Jeff R.

Archived from groups: rec.photo.digital.slr-systems (More info?)

On Sat, 10 Sep 2005 23:27:54 -0400, Ed Ruf <egruf_usenet@cox.net>
wrote:

>On Sat, 10 Sep 2005 22:12:52 -0400, in rec.photo.digital.slr-systems Rich
><none@none.com> wrote:
>
>>I've seen quite a few shots of animals recently where the photogs
>>coudn't get too close, for various reasons. What struck me was that
>>although the shots were sharp, they were obviously heavily cropped
>>because noise was evident in them. Noise in pro DSLRs is "attractive"
>>in a film-like way, but the cropping still reduces the overall quality
>>of the image. If a photog is using a 600mm lens with a converter to
>>get 1200mm, and it's still not enough to avoid heavy cropping, maybe
>>it's time to get away from long refractive telephotos and into reflex
>>systems that would allow much greater focal lengths while maintaining
>>a reasonable focal ratio? The only drawback of course would be the
>>inability to stop-down and the attendent short depth of field. But,
>>there are lens systems out there that can provide focal lengths in the
>>2500mm range with f6.3 focal ratios. No autofocus though.
>
>And the brokeh looks like what?

Maybe we could learn to like the christmas tree-like defocussed circle
of light?
If the idea is to capture the animal (or whatever) in the best detail
possible, and not to make artistic pictures, it wouldn't matter about
the background.
-Rich

Archived from groups: rec.photo.digital.slr-systems (More info?)

On Sun, 11 Sep 2005 18:09:19 +1000, "Jeff R" <contact.me@this.ng>
wrote:

>
>"Stacey" <fotocord@yahoo.com> wrote in message
>news:3oi410F62362U4@individual.net...
>> Ed Ruf wrote:
>>
>> > On Sat, 10 Sep 2005 22:12:52 -0400, in rec.photo.digital.slr-systems
>Rich
>> >The only drawback of course would be the
>> >>inability to stop-down and the attendent short depth of field. But,
>> >>there are lens systems out there that can provide focal lengths in the
>> >>2500mm range with f6.3 focal ratios. No autofocus though.
>> >
>> > And the brokeh looks like what?
>> >
>>
>> Ugly beyond words?
>>
>> I own one mirror lens and it's such a PITA to use and produces such UGLY
>> bokeh, the only thing it can even be used for is maybe a bird or something
>> in water or in the sky.
>
>
>Some folks like it, some folks don't.
>http://mendosus.com/jpg/gumnuts.jpg
>Some folks don't care either way.
>
>This example is a particularly *aggressive* one.

That, I admit is pretty horrible. It's a good example of why
refractive elements still dominate the field. But some pictures
(say a lion on the Savannah) won't produce that kind of effect since
specular highlights on the high grass likely won't happen, or will be
so subdued that they won't produce that kind of effect.
-Rich

Archived from groups: rec.photo.digital.slr-systems (More info?)

Rich wrote:
> On 11 Sep 2005 10:22:43 -0700, "Jan Böhme" <jan.bohme@sh.se> wrote:

> >digiscoping.

> Main problem is speed. I've seen the calculations and when using (for
> example) and 80mm scope to produce a 2000mm focal length, you're
> f-ratio becomes 25.

Not something for dawn or dusk, agreed. But I have a friend who does
digiscoping with a Swarovski ATS-80 HD vith a 20x eyepiece, a
digiscoping adapter, and a Nikon CP 995. (He used to borrow my Coolpix,
that's how I got into it.) He can get decent pics at full zoom, which
would have a focal equivalent of just over 3000 mm, and an f-ratio of
just under 40, according to your calculations, also when the bird isn't
in bright sunlight.

> P&S shooters have no choice in this, they have
> to use an eyepiece to get an image owing to the fact their camera
> lenses are fixed. Here's a shot I took at 4000mm using a telescope
> with a 125mm wide front aperture. F-ratio was (4000/125) 32.

I agree that the extra three stops of ISO sensitivity you get in a DSLR
must be very useful when shooting through a telescope, and there are
cheap adapters that allow a DSLR to me coupled to a telescope. OTOH,
then you can't use the camera lens of the digicam for extra zoom. Given
the same scope, you get a lot more of both light and sensitivity, but
considerably less equivalent focal length.

In theory, it should be possible to hook up a DSLR, lens and all,
behind a telescope, just as the P&S shooters do with their digicams.
Then, one would take advantage of the three extra stops of sensitivity,
without having to compromise on equivalent focal length.

But I have never seen it done. And nomal lens diameters of SLR lenses
aren't exactly ideal for digiscoping purposes.

Jan Böhme

Archived from groups: rec.photo.digital.slr-systems (More info?)

On Thu, 15 Sep 2005 17:57:23 +0100, David Littlewood
<david@nospam.demon.co.uk> wrote:

>In article <hl39i1hsh0a62tva0qu3qnipicpad4d07l@4ax.com>, Rich
><none@none.com> writes
>>On Sun, 11 Sep 2005 03:27:01 GMT, JPS@no.komm wrote:
>>
>>>In message <fa47i193dvptd5bcdh2cu612a9psvgin7d@4ax.com>,
>>>Rich <none@none.com> wrote:
>>>
>>>>I've seen quite a few shots of animals recently where the photogs
>>>>coudn't get too close, for various reasons. What struck me was that
>>>>although the shots were sharp, they were obviously heavily cropped
>>>>because noise was evident in them. Noise in pro DSLRs is "attractive"
>>>>in a film-like way, but the cropping still reduces the overall quality
>>>>of the image. If a photog is using a 600mm lens with a converter to
>>>>get 1200mm, and it's still not enough to avoid heavy cropping, maybe
>>>>it's time to get away from long refractive telephotos and into reflex
>>>>systems that would allow much greater focal lengths while maintaining
>>>>a reasonable focal ratio? The only drawback of course would be the
>>>>inability to stop-down and the attendent short depth of field. But,
>>>>there are lens systems out there that can provide focal lengths in the
>>>>2500mm range with f6.3 focal ratios. No autofocus though.
>>>
>>>Might work for a bird on a wire, or in the sky, but the bokeh would be a
>>>mess for an animal in the brush or in a tree.
>>
>>There is no way around the blurred "donuts" unfortunately.
>>-Rich
>
>Actually, I think there is.
>
>The "doughnut" effect is caused by the secondary mirror which is
>normally placed in the centre of the front refractor (or plain glass) in
>a mirror lens. This knocks a hole out of the light, which because of the
>optics is not apparent in perfectly focussed areas but is clearly
>visible in out of focus areas. There is however a design in which the
>first mirror (the big one at the camera end) is slightly skewed, and the
>secondary mirror is off to one side. This means it does not knock out
>the middle of the image-forming bundle, hence there are (or should be)
>no doughnuts.
>
>ISTR seeing at least one astronomical telescope being marketed recently
>which uses this design. I have not seen it in any lens sold for
>photographic use, but I guess this thread was specifically discussing
>the former.
>
>If anyone is interested, I will try to find details, I may still have
>the magazine which described it.
>
>David

Only problem; They are very "slow" (f-ratio) scopes.
Off-axis Newtonians from Oriontel.com
-Rich