Can someone here explain to DSG why his theory of diffraction is backwards.

[ole thofte]

Sweet spots are not always the same though.

On top lenses most are as sharp WO as they are at F4 and by F8 you
are losing some rez although you would never see that loss on a SD.
Basically the sweet spot is the entire range from WO to F8.

Lenses like the latest Leica 35mm asph lens, some contax, the
latest zeiss lenses, digitars etc. are a few

Superior optics rules in my book.

Now Sigma needs to step up to the plate with some upgraded optics.

I'll take your word for that about the sweet spot. But is that usable on a Sigma camera? Can these lenses be used in some way on a Sigma xx? I'm thinking: if you were willing to strip (ruin) part of the front end of the camera in order to fit some of these lenses for manual use. (you have 7 mm from the front to the dust protector) Even if you can't use Sigma or other lenses anymore...

In my mind though the superior optics don't enter before I've managed to control all other interfering factors like camera shake and focussing correctly for the given subject. And I haven't....

Ole

--
http://www.pbase.com/thofte

 

[Frits Thomsen]

Sweet spots are not always the same though.

On top lenses most are as sharp WO as they are at F4 and by F8 you
are losing some rez although you would never see that loss on a SD.
Basically the sweet spot is the entire range from WO to F8.

Lenses like the latest Leica 35mm asph lens, some contax, the
latest zeiss lenses, digitars etc. are a few

Superior optics rules in my book.

Now Sigma needs to step up to the plate with some upgraded optics.

I'll take your word for that about the sweet spot. But is that
usable on a Sigma camera? Can these lenses be used in some way on

Ole the new carl Zeiss ZF series could be used on your Sigma with the Nikon/Sa adapter... later they will also introduse these lenses in M42 mount (ZM ?) This link ( Carl Zeiss) claims these are the sharpest lenses they have ever tested...
http://www.zeiss.com/photo

a Sigma xx? I'm thinking: if you were willing to strip (ruin) part
of the front end of the camera in order to fit some of these lenses
for manual use. (you have 7 mm from the front to the dust
protector) Even if you can't use Sigma or other lenses anymore...
In my mind though the superior optics don't enter before I've
managed to control all other interfering factors like camera shake
and focussing correctly for the given subject. And I haven't....

Ole

--
http://www.pbase.com/thofte

--
Frits Thomsen
See my pictures at
http://www.pbase.com/yoicz

 

[DaSonyGuy]

But it seem he has totally neglected to mention how lens
abberations effect lens sharpness at wider apertures

The only "total neglect" was you failing to read the article
carefully to the end. (Hint: look in the section called "Notes on
Real World Use in Photography")

Your right, I did'nt see the bit at the end, but it does'nt alter the fact he is only stating what I have already said, only in another way.

virtually all lenses sharpest when stopped down at least by one
stop but often several,

Here is where Alf-speak leaves the more pedantic among us reaching
for Dom's headbanger gif. The common definitions of "often" and
"several" don't seem to match your usage.

Well perhaps thats because I actually speak English, and as an American you only think you do!

and not WO as the article above suggests.

The article suggests nothing of the kind. In fact, it's primary
purpose is how to find the point where diffusion begins to dominate
even DOF.

Even once you are past the len's optimum aperture, you
may wish to stop down more to get additional effective sharpness at
points other than exact focus point. But there is a point where
stopping down more doesn't even buy effective DOF because you are
now diffusion dominated.

Sheesh, I wish people would take the trouble to read all the replies before reaching for their keyboard and repeating what has already been said upteen times!

Regards

DSG
--
http://sigmasd10.fotopic.net/

 

[ole thofte]

Ole the new carl Zeiss ZF series could be used on your Sigma with
the Nikon/Sa adapter... later they will also introduse these lenses
in M42 mount (ZM ?) This link ( Carl Zeiss) claims these are the
sharpest lenses they have ever tested...
http://www.zeiss.com/photo

Hi Frits, good to hear from you again! I have the best portrait of you I've seen. Got it from Chris. I thought he took it, but it turned out I did Wouldn't you like to see it?

I remember this Zeis being mentioned before on the forum. Is it interesting? I saw the price for 50mm f1.4 was around 500 Euro, and the 85mm f1.4 around 1000 Euro. Quite a bit for manual lenses but not impossible if there was a good reason to get one of them... do you think there is?

Ole

--
http://www.pbase.com/thofte

 

[DaSonyGuy]

Ole the new carl Zeiss ZF series could be used on your Sigma with
the Nikon/Sa adapter... later they will also introduse these lenses
in M42 mount (ZM ?) This link ( Carl Zeiss) claims these are the
sharpest lenses they have ever tested...

The M42 versions are labled: ZS....You might have trouble getting over the psychological barrier of paying so much for M42 mount lenses though.

Regards

DSG
--
http://sigmasd10.fotopic.net/

 

[Truman Prevatt]

Then I wonder why the guys famous for sharp images formed the group called F64?

--
Truman

 

[ole thofte]

Ole the new carl Zeiss ZF series could be used on your Sigma with
the Nikon/Sa adapter... later they will also introduse these lenses
in M42 mount (ZM ?) This link ( Carl Zeiss) claims these are the
sharpest lenses they have ever tested...

The M42 versions are labled: ZS....You might have trouble getting
over the psychological barrier of paying so much for M42 mount
lenses though.

Yeah, there's something. And since I allready have 4 pretty good m42 50mm I don't use that much, the barrier is steep. But then I don't have any 85mm m42 ... and if it's the best....

Ole
--
http://www.pbase.com/thofte

 

[tammons]

Sweet spots are not always the same though.

On top lenses most are as sharp WO as they are at F4 and by F8 you
are losing some rez although you would never see that loss on a SD.
Basically the sweet spot is the entire range from WO to F8.

Lenses like the latest Leica 35mm asph lens, some contax, the
latest zeiss lenses, digitars etc. are a few

Superior optics rules in my book.

Now Sigma needs to step up to the plate with some upgraded optics.

I'll take your word for that about the sweet spot. But is that
usable on a Sigma camera?

Yes. I have a contax lens that is very sharp WO. Its basically as sharp WO as most EX SA lenses are at F4.

Can these lenses be used in some way on
a Sigma xx? I'm thinking: if you were willing to strip (ruin) part
of the front end of the camera in order to fit some of these lenses
for manual use. (you have 7 mm from the front to the dust
protector)

Can be converted to M42 but its not easy.

The upcoming Zeiss M42 lenses should be much better. Any of the new Zeiss lenses should show a zero pixel edge WO. Also you could go the nikon SA adapter route

Even if you can't use Sigma or other lenses anymore...
In my mind though the superior optics don't enter before I've
managed to control all other interfering factors like camera shake
and focussing correctly for the given subject. And I haven't....

Camera shake shooting WO should not be a problem. Got to have a split screen to shoot any manual lens around WO.

Ole

--
http://www.pbase.com/thofte

--
http://www.troyammons.com
http://www.pbase.com/tammons
http://www.troyammons.deviantart.com

 

[tammons]

I remember this Zeis being mentioned before on the forum. Is it
interesting? I saw the price for 50mm f1.4 was around 500 Euro, and
the 85mm f1.4 around 1000 Euro. Quite a bit for manual lenses but
not impossible if there was a good reason to get one of them... do
you think there is?

You really have to think about it in different terms. These lenses are really an overkill for a sd9 with 54lp/mm since it only takes a 100lp/mm lens to fully resolve a SD. Put it on a 100lp/mm dslr and thats a different story.

Also mount the 25mm lens on a film body with MLU and a 50# tripod some microfilm like bluefire and you would be resolving around 250 lp/mm.

To put that into perspective it would take a 12000 dpi drum scan to resolve maybe 200 lp/mm. A 12000 dpi scan equates to 192 mp from 35mm although an 8000 dpi scan would be more realistic. 8000 dpi works out to 85mp from a 35mm frame.

All of that plus zero CA and super sharp WO is what makes a lens worth $600-1000. Actually that is fairly cheap compared to the latest Leica 35mm asph lens that cost $3000.

Its a life time investment for a perfectionist, else you can just convert a Contax CY lens.

Shooting a lens like that is like a photographic weight lifted off your shoulders. You never have to worry about soft photos from aberrations or any CA at all. It really frees up shooting.

The problem with the SD is mostly the exposure is not accurate with a manual lens.

Ole

--
http://www.pbase.com/thofte

--
http://www.troyammons.com
http://www.pbase.com/tammons
http://www.troyammons.deviantart.com

 

[tammons]

I can tell you for a fact, that shooting an 8x10 or larger camera at F32 - F64 is a must. A normal lens is long for 8x10. 300mm so try to get some decent dof out of that at F8.

Shooting an 8x10 camera at F64 is an exercise in frustration too and impossible if anything is moving and you cant always tilt.

I figure thats why these guys shot so many inanimate objects.

Also I would assume most of those lenses used back then were coke bottles except for maybe the cooke lenses and a few others.

With 8x10 the film is so big resolving 35-40 lp/mm is just fine so stopping way down is no big deal.

--
http://www.troyammons.com
http://www.pbase.com/tammons
http://www.troyammons.deviantart.com

 

[JoePhoto]

Sheesh, I wish people would take the trouble to read all the
replies before reaching for their keyboard and repeating what has
already been said upteen times!

Yep .... you can say that again .... ..... and again ...

Regards

DSG
--
http://sigmasd10.fotopic.net/

--
Thanks for reading .... JoePhoto

( Do You Ever STOP to THINK --- and FORGET to START Again ??? )

 

[ole thofte]

I remember this Zeis being mentioned before on the forum. Is it
interesting? I saw the price for 50mm f1.4 was around 500 Euro, and
the 85mm f1.4 around 1000 Euro. Quite a bit for manual lenses but
not impossible if there was a good reason to get one of them... do
you think there is?

You really have to think about it in different terms. These lenses
are really an overkill for a sd9 with 54lp/mm since it only takes a
100lp/mm lens to fully resolve a SD. Put it on a 100lp/mm dslr and
thats a different story.

Thanks Troy! Forgive me if I'm a bit slow in these matters - If I understand you correctly these lenses are overkills for both sd9 and 10 in terms of resolution. The new camera we have to see about So you would have to look for something else camerawise. Which I (probably) wouldn't do for practical and economical reasons....

Out of curiosity: how do you know the sd9 resolves 54 lp/mm? And what would be a 100 lp/mm dslr?

Also mount the 25mm lens on a film body with MLU and a 50# tripod
some microfilm like bluefire and you would be resolving around 250
lp/mm.

To put that into perspective it would take a 12000 dpi drum scan to
resolve maybe 200 lp/mm. A 12000 dpi scan equates to 192 mp from
35mm although an 8000 dpi scan would be more realistic. 8000 dpi
works out to 85mp from a 35mm frame.

All of that plus zero CA and super sharp WO is what makes a lens
worth $600-1000. Actually that is fairly cheap compared to the
latest Leica 35mm asph lens that cost $3000.

OK - that makes me understand it's quite an achievement from Zeis to offer these lenses!
And the price is fair....

Its a life time investment for a perfectionist, else you can just
convert a Contax CY lens.

Shooting a lens like that is like a photographic weight lifted off
your shoulders. You never have to worry about soft photos from
aberrations or any CA at all. It really frees up shooting.

Here you give a reason to get a Zeis in spite of the above reason not to overkill. I just don't know how much that would mean in everyday photography with the Sigmas...

The problem with the SD is mostly the exposure is not accurate with
a manual lens.

Yeah, but that can be handled with some experience and experimenting. Even if lately I've realized, what has been said from the beginning of course, that correct exposure is really important for the Sigma camera. You can correct a lot in SPP, but correct exposure makes you avoid the usual problems with noise, blowouts etc.

And that it's somewhat of an art using the right WB and metering system (the right way) to get accurate AE anyway.

So I have 1,5 reasons to get a Zeis and 1,5 reasons not to get it :-7

Ole
--
http://www.pbase.com/thofte

 

[Frits Thomsen]

Ole the new carl Zeiss ZF series could be used on your Sigma with
the Nikon/Sa adapter... later they will also introduse these lenses
in M42 mount (ZM ?) This link ( Carl Zeiss) claims these are the
sharpest lenses they have ever tested...
http://www.zeiss.com/photo

Hi Frits, good to hear from you again! I have the best portrait of
you I've seen. Got it from Chris. I thought he took it, but it
turned out I did Wouldn't you like to see it?

Hmmm welll ok .... since you have taken it ... i might just as well see it...

I remember this Zeis being mentioned before on the forum. Is it
interesting? I saw the price for 50mm f1.4 was around 500 Euro, and
the 85mm f1.4 around 1000 Euro. Quite a bit for manual lenses but
not impossible if there was a good reason to get one of them... do
you think there is?

If the new Sigma will have more resolution than our SD10´s we might need some better lenses to rerally take advantage from that higher resolution... With these CZ lenses you wont ever have to worry about the lens as a limiting factor.
Did you find the really interesting parts on that CZ site...??
here is a guide....
http://www.zeiss.com/photo

then click on "camera/cine-lenses", then click on "newsletter" in the left side menu", then click on "24 february 2006" .
Scrolling down you will find these informations:
" The 1,4785ZF have a test result of 250 lp/mm from f 5,6 to 2,0..

and the 1,4/50 ZF will do even better ... 320 lp/mm from f5,6 to 2,8 and 250lp/mm at f2,0..."

Ole

--
http://www.pbase.com/thofte

--
Frits Thomsen
See my pictures at
http://www.pbase.com/yoicz

 

[tammons]

Thanks Troy! Forgive me if I'm a bit slow in these matters - If I
understand you correctly these lenses are overkills for both sd9
and 10 in terms of resolution. The new camera we have to see about
So you would have to look for something else camerawise. Which
I (probably) wouldn't do for practical and economical reasons....

Not really. Buying one of the new Zeiss lenses would be the last manual prime you would ever buy in that FL. Its an overkill now but maybe not in the future.

Out of curiosity: how do you know the sd9 resolves 54 lp/mm?

One line pair = two rows of dots on the SD.

Rez in one direction / size in MM = lines per mm / 2 = line pairs

And
what would be a 100 lp/mm dslr?

Talking Foveon but that would be a .........

35.5 mp full frame chip

11.5 mp chip at the current 1.7x crop ratio

9 mp 4/3 chip

Also mount the 25mm lens on a film body with MLU and a 50# tripod
some microfilm like bluefire and you would be resolving around 250
lp/mm.

To put that into perspective it would take a 12000 dpi drum scan to
resolve maybe 200 lp/mm. A 12000 dpi scan equates to 192 mp from
35mm although an 8000 dpi scan would be more realistic. 8000 dpi
works out to 85mp from a 35mm frame.

All of that plus zero CA and super sharp WO is what makes a lens
worth $600-1000. Actually that is fairly cheap compared to the
latest Leica 35mm asph lens that cost $3000.

OK - that makes me understand it's quite an achievement from Zeis
to offer these lenses!
And the price is fair....

Its up in the air if Leica is overcharging by $2000 or Zeiss has found a more efficient way to grind and coat lenses. More likely Leica is charging for the name. I mean a M7 rangefinder body cost $3500. The special edition camera with a 50mm lens cost $9000.

Its a life time investment for a perfectionist, else you can just
convert a Contax CY lens.

Shooting a lens like that is like a photographic weight lifted off
your shoulders. You never have to worry about soft photos from
aberrations or any CA at all. It really frees up shooting.

Here you give a reason to get a Zeis in spite of the above reason
not to overkill. I just don't know how much that would mean in
everyday photography with the Sigmas...

Like I said shooting a lens at this level is like a weight lifted off your shoulders. After shooting one lens that is tack sharp WO you will be ruined for life.

The problem with the SD is mostly the exposure is not accurate with
a manual lens.

Yeah, but that can be handled with some experience and
experimenting. Even if lately I've realized, what has been said
from the beginning of course, that correct exposure is really
important for the Sigma camera. You can correct a lot in SPP, but
correct exposure makes you avoid the usual problems with noise,
blowouts etc.
And that it's somewhat of an art using the right WB and metering
system (the right way) to get accurate AE anyway.

Hopefully they will fix that with the next camera.

So I have 1,5 reasons to get a Zeis and 1,5 reasons not to get it :-7

Ole
--
http://www.pbase.com/thofte

--
http://www.troyammons.com
http://www.pbase.com/tammons
http://www.troyammons.deviantart.com

 

[Truman Prevatt]

I can tell you for a fact, that shooting an 8x10 or larger camera
at F32 - F64 is a must. A normal lens is long for 8x10. 300mm so
try to get some decent dof out of that at F8.

I've never shot an 8x10 but quite a bit of 4x5 and even on a 4x5 one normally one has to stop down to f32 or greater. Even then you need swings and tilts to control the focal plane simply because the for the same field of view the lenses have to be longer as the sensor format gets bigger.

I figure thats why these guys shot so many inanimate objects.

You forget about Weston's beloved Tina - of which he took many photos nude on the beaches of Mexico .

Also I would assume most of those lenses used back then were coke
bottles except for maybe the cooke lenses and a few others.

The Schneider and high end Rodenstock lenses were (are quite good) and quite expensive. The Schneider 150 (apx. 50 mm 35 mm equiv.) goes for a little over two grand and the Rodenstock 240 (axp 80 mm 35mm equiv) goes for just a little under two grand. The are both very good glass - maybe better than anything found for 35 mm excpet the top lenses. These lenses are quite simple, focusing is done by moving the lens note by an internal mechanism so the cost is the cost of the glass and shutter.

With 8x10 the film is so big resolving 35-40 lp/mm is just fine so
stopping way down is no big deal.

Yes it does get down to the size of the negative compared to the size of the final image. An 8x10 print is a contact print of an 8x10 negative. An 8x10 print is a 2 x magnification (linear dimensions) of a 4x5 negative.

The newer digital sensors greater than maybe 10 Megapixels have amazing resolving powers and it takes an super lens to support them.

--
Truman
http://www.pbase.com/tprevatt

 

[ole thofte]

Thanks Troy - I'll put that in my pipe and smoke it :-7

Ole
--
http://www.pbase.com/thofte