Canon 24 ts on Hcam vs tecnical cameras with real LF lenses?

[henrikfoto]

Is molding of these elements seen as the best way to get the maximum quality or does it have any negative effect on the image-quality in any way?

I wonder if Schott can do these molding why can't Zeiss, Schneider, Rodenstock etc?
Or is there any reason they prefer not to?

Henrik

[Stefan.Steib]

Hi Henrik

grinding of lenses will produce a yield of quality which differs for each lens, not much, but enough so that the ISO Norm on focal lenght of a 100 mm lens
may supply you with either a 95mm or a 105mm lens within the same batch of production !!!

In contrast to this I am pretty sure that molded lenses are having nearly identical focal lenghts and other optical data for each and every lens produced.

Schott makes many if not all (or at least made) of the Zeiss lenses (Made in Germany), whereas today I think Cosina/Zeiss uses Hoya glass (this is probably as good !)

And finally : the devellopment of such a technology probably costs a fortune, even for a large company. Now take into account the numbers that Qioptiq(Rodenstock)
and also Schneider Kreuznach produce in this area and compare this to the volume that Canon does. I think this says it all. No way you will ever see such a Rodie or Schneider. ..........too expensive for them.

So who is selling the Hightech here ?

Greetings from Munich
Stefan

[henrikfoto]

Thank you, Stefan!
This is very interesting and I think very little known by most people.
I had no idea Zeiss glass was not made by zeiss....

Do Canon somewere have information about what size image-circle their different lenses produse?

Henrik

[Stefan.Steib]

Hi Henrik

If I knew a source for this I´d be the happiest person on the planet, but this does not exist..........
You have to try each and every lens by yourself, but - hopefully when more people use HCam, we will finally get into the knowledge
where the pearls are hidden.
One more hint: Many Leica R lenses (very likely) and Contax Glass use to have larger image circles past 50mm.
This probably as they have actually built lenses with larger image circles to utilize the sweetspot of the larger diameter to improve uniformity.

Regards
Stefan

[ErikKaffehr]

Hi Stefan,

Didn't want to argue with you on that point ;-)

I read an article about optical glass in C't a couple of years ago, and they mentioned two kinds of glass that could be used for molded lenses.

The poster I was responding to stated that Leica tried molded aspherics and found them impractical.

As far as I understand essentially all modern lenses use molded aspherics, but probably small ones, as you mentioned.

The images you posted are awesome, but look a bit over sharpened to me. That camera is an impressive device!

By the way, how do you focus?

Best regards
Erik

Hi Erik

I knew the link from Schott - the point is the Size and the extremety of curvature that Canon can do (remember the 17mm front lens ! This linked cine lens in my earlier post is probably using even bigger sizes ! ) , Schott defines it limited as follows:

    Lens diameter: 1,5 – 35 mm
    Lens thickness: 0,5 – 10 mm
    Radius of curvature convex: > 3 mm
    Radius of curvature concave: > 5 mm

Which means - Schott cannot do the frontlens of the 17mm TSE. And probably nobody else than Canon.

Regards
Stefan

[uaiomex]

Original picture is 5530X6661px from a stitch made with the 5D2 and the 17TS @f9.0
Eduardo

[Stefan.Steib]

Hi Eric

I focus with the Groundglass ! We have taken large efforts to get this sorted out and now every HCam-B1 that leaves factory is calibrated to the groundglass.
As a consequence we have now fixed the viewfinder adapter with screws to the HCam-B1 Body.  As a standard we deliver a third party focusing screen, but we have more and more customers now which take the chance and either buy or supply us their own Arcbody/SWC viewfinder adapter latest Acumatte version with grid - which is certainly the best screen available, unfortunately it is not made new anymore.
As the Canon Lenses are f3,5 respectively f4   this is a full or 1,5 stops brighter than a comparable Rodie or Schneider WA lens . This helps a LOT !
This is even better when you have f2,8 or f1,4 (e.g. Zeiss 85mm Planar) to focus on the HCam. This works as easy as on a 35mm camera, but with the precision of a 4xLoupe as I used it on my Viewcamera.
So the yield of sharp images is pretty good, even if you only use the optical finder, if I want to be 100 % sure, I do 3 shots  a tad front focus, as in the finder and a bit backfocus
because sometimes the spherical character of the extreme wideangle 17+24mm will help to achieve unbelievable sharpness even into the corners.
My theory is that many people who do complain the borders with these TS-E´s are not sharp do not understand how much this spherical character influences the  sharpeness
area. Once you got it you can do incredible things with it (Interiors, Architecture, Landscape....)

Greetings from Munich
Stefan