DPR Forum

Welcome to the Friendly Aisles!
DPRF is a photography forum with people from all over the world freely sharing their knowledge and love of photography. Everybody is welcome, from beginners to the experienced professional. Whether it is Medium Format, fullframe, APS-C, MFT or smaller formats. Digital or film. DPRF is a forum for everybody and for every format.
Enjoy this modern, easy to use software. Look also at our Reviews & Gallery!

Carl Zeiss 21mm Distagon f2.8

>>>>>>>>>>>> I've used a Cokin A system with an 85mm > portrait lens (67mm thread, stepped down to 62mm) and managed to scrape away > at f8... > any wider, I get pretty pictures of my filter holder>>>>>>>>>>>>> You can take photos at different apertures with a filter to determine if it vignettes.

I have placed some groundglass material (translucent--blank film with scotch magic tape (not clear) over it) in the film plane. Open the shutter and observe the effect with the lens stopped down. I have found that the vignetting is worse at the smaller apertures than wide open. This is more accurate than just looking at the finder, unless your SLR shows 100% of the film area. Most do not, to compensate for the masked off section of the slide mount. Doesn't the RTS III show 100% of the film area?
 
> >..Open the shutter and observe the effect with the lens stopped down. I have found that the vignetting is worse at the smaller apertures than wide.<

I wondered about all the postings about vinetting wide open. I put my D25 with a filter and the hood on my RTS III and can only see the vignetting at small apertures with the DOF preview and not at the large ones. To show my complete ignorance, if you could see vignetting at large ap's and not at small ones, wouldn't this be like changeing the focal length with the aperture ring? Jeff
 
> I wondered about all the postings about vinetting wide open. I put my> D25 with a filter and the hood on my RTS III and can only see the> vignetting at small apertures with the DOF preview and not at the > large ones. To show my complete ignorance, if you could see vignetting> at large ap's and not at small ones, wouldn't this be like changeing> the focal length with the aperture ring? Jeff

I am only talking about mechanical vignetting , not light fall off in the corners due to design factors etc etc etc Steve
 
> Using the experience of my large format camera, where you detect vignetting from the film plane, I opened the shutter and camera back and sighted from the rear, from the corner into the lens. Vignetting is always worse at large apertures, so starting from f2.8 I could see the () shape of the outer lens flange. Only when I had stopped down to f8 could I see the entire aperture ring, defining the end of vignetting performance.

Chris Woodhouse ARPS
 
>Do try the "P"size ones first...
What I am going to tell you now might sound funny to your ears, but..
As I stated above, I rarely use filters with the D21. However, when I am travelling (which is what I usually do when I take pictures), then I always have a collection of Cokin P-filters with me. Since space and weight are important issues, I renounce the usual holding device and simply hold the filter-glass in front of the lens. This works perfectly even with the D21 - if you pay a little attention to where you place your fingertips;)
Marc
 
Hey Marc -

That's what I tried to do with a standard lens; the wind blew ferociously, and my tripod pan head let go of tension rather dramatically, and I had a choice to catch the camera or the Cokin filter.

The filter bit the dust; thankfully it was only a Cokin.

By the way, I've ordered the 21mm lens after all. I'm looking forward to peering up people's faces to see whether it is truly distortion free
happy.gif


Joe99
 
Hi Joe,
In such situations I always recommend to hunt for the camera, especially with D21 mounted ;-)
All else you can do is looking for a dealer who sells Cokin P with a hefty discount if you take them by the dozen.
Please let us know about people's reaction to your lens-testing mission...
Cheers,
Marc
 
21mm f2.8

Hi Marc

Yes - sometimes I wish I was modern enough to use a slide-scanner, then I could download my future lens-testing mission on the gallery (no doubt to be slated by rotten e-tomatoes!)

Just another thought on this lens (I'm starting to distort in what seems like an interminable wait for this lens); will an extension tube work with anything as wide as this, or will that include the photographer in the picture? Maybe an extension tube will force a minimum focus distance dangerously close to the fist of the photographed person, landing me up with a knuckle up my 21mm f2.8?


Joe99
 
Back
Top