Review: Digiscoping with the Zeiss Diascope 85FL (1 Viewer)

RonR

Active member

• Aug 9, 2003

• #21

I had an opertunity to visit with an Ziess representitive at a sports show, what an experience, did not get his name as I was to busy learning. Being I have a Sony F707 I wanted to see what could be done with the Zeiss - was working with the 65 and it did a very good job, being we were inside and not much to focus on, we used a barcode on another exibitors stock, recommended I get to a dealer an try the 85 and wait till Zeiss comes out with the mount for the Sony - he told me how it would operate and it sounded like it would be the "cats meow".
We'll wait and see.

 

Mugil

Well-known member

• Sep 27, 2003

• #22

Quick Camera Adapter

Hello everybody,

I am digiscoping for certain period with Zeiss Diascope 85 T FL with Quick Camera Adapter and there is no or very few vignetting. This Adapter costs cca. 300 EUR (mybe somewhere is less). The only problem I have got is that in this adapter I can not use my home made Cable Release Bracket because of too short screw (I must make one longer), thats why I am still using my Kowa TSN 2 with a home made tube-like device with a thread at one end to attach to the camera lens’s filter thread.
By the way I think that in fluorite lenses is necesary to have light coloured scopes (silver, white...) and suppose that green should not be used because of heat. But mybe I am wrong.

 

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M

mak

Well-known member

• Sep 28, 2003

• #23

Mugil.
The green version operates the same as the silver version. The lenses have nothing to do with the body colour.

 

Mugil

Well-known member

• Sep 28, 2003

• #24

Can you explain why are all those profesional SRL objectives of Canon and Nikon in white or silver colours? As far as I know this is because of fluorite lenses!

 

Adey Baker

Member

• Sep 29, 2003

• #25

The refractive index of fluorite is affected by the temperature so I'm sure this is why lenses/scopes with fluorite elements are usually light-coloured - to reflect heat away.

Canon have used fluorite in their large-aperture telephoto lenses for decades - hence the pale off-white colouring has become almost a 'trademark' for them.

As far as I'm aware, Nikon use only 'ED' glass rather than fluorite for their camera lenses.

In the UK at least Nikon tele-lenses are black with the white-coloured versions only available to special order. I've seen one reference to the white ones being 'prefered by wildlife photographers' - which is interesting!

 

Mugil

Well-known member

• Sep 29, 2003

• #26

Adey thanks, this is the reason of my comment about scopes body green colour.

 

M

mak

Well-known member

• Sep 30, 2003

• #27

Mugil / Adey Baker
I stick to my original comment that the colour will make no difference and this is why:
Calcium Fluoride (CaF2) has a thermal expansion coefficient of 18.85*10 exp -6/K
Fluoron Crown has between 13.1x10 exp -6K and 14.5*10 exp -6K and BK7 has 7.1*10 exp -6K
All thermal expansion coefficients are related to -30 degrees C to +70 degrees C.
As you can see there is no dramatic difference btw the thermal expansion coefficient.
Thus an increase in distortion caused by thermal expansion of the lenses is rather unlikely.

 

ps11aj

Pierre

• Oct 12, 2003

• #28

Is there a difference in light and sharpness between a fixed 20x eyepeace or a zoom 20-60x at 20x? I am concidering a spottingscope with fluorite to next spring for digiscoping and birdwatching. It is for the digiscoping use I wonder.
Regards Pierre Stjernfeldt

 

Adey Baker

Member

• Oct 12, 2003

• #29

Mak

Sorry I missed your Sept 30th reply first time round - I was basing my comments on Leica literature for the change of refractive index and the test report on Sigma lenses by the late Stewart Bell in 'Amateur Photographer' for colour of lens body remarks

Adey

 

ps11aj

Pierre

• Nov 18, 2003

• #30

I have seen many very good pictures taken with the Leica Apo and Swarovsky ATS/ST on this site, but it is harder to find pictures taken with Zeiss diascope.
Pierre

 

J

Jay Turberville

Well-known member

• Nov 18, 2003

• #31

ps11aj said:

Is there a difference in light and sharpness between a fixed 20x eyepeace or a zoom 20-60x at 20x? I am concidering a spottingscope with fluorite to next spring for digiscoping and birdwatching. It is for the digiscoping use I wonder.
Regards Pierre Stjernfeldt

Click to expand...

This probably depends a lot on the particular eyepiece and scope. I compared a 20xSW with a 20-60x Swarovski zoom on an ATS80HD this weekend and my preliminary finding is that they are very close in sharpness. The zoom at 20x seems to have slightly less magnification and also has a slightly flatter field though.

If considering a relatively inexpensive eyepiece, I would definitely lean toward a fixed focal length. But the very best zoom eyepieces seem to be every bit as sharp as fixed focal length eyepieces. They usually give up some AFOV (its usually noticabley narrower) and cost a bit more though.