my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Scope lens issue

Author Topic: Scope lens issue Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 07-08-2017 09:55 AM                     I have an Isco 135MM 35/70 lens for scope. I tried 3 different Schneider standard anamorphics on them and I can't focus. The 135MM lens focuses perfectly by itself. I even tried another 135MM lens and still the same issue. I then unscrewed the anamorphic and held it an inch or 2 away from the lens and it focused fine. Would I normally need a spacer for this?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-08-2017 03:09 PM                     Your problem is the crappy Schneider (full size) anamorphic lenses. I'm not kidding. They are pure crap. The VERY last generation of them were fine, as far as 4-4-element anamorphics go but all of the 1980s - through 1990s anamorphics are junk. Depending on how much their elements have shifted is how bad they are. Their integrated anamorhpics didn't have the problem but are not recommended for long EF (135mm) primes. Put an ISCO (any generation) on those same 135mm lenses and it will be like getting new eyes. As you move up in ISCO lens grades (4-element through 6-element) you'll see the aberrations decrease.  |  IP: Logged Jonathan Wood Expert Film Handler Posts: 206 From: Oxfordshire, United kingdom Registered: Jan 2008 posted 07-30-2017 01:28 PM                     Hi Richard, how close are you trying to focus ? I assume since your using a 135mm backing lens then your not talking about a short throw ? Steve's comments are very interesting - I have both Isco and Schneider integrated lenses and I do prefer the Isco - it's got a nicer colour balance and it's sharper . Never tried a full sized Schneider attachment , I do have an a Isco attachment but never felt the need to use it since the integrated works so well.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-30-2017 03:24 PM                     Other than the three ISCO Blue-start integrated anamorhics, all of ISCO integrated anamorhpics were based on their 4-elemenet design, that didn't change throughout the years. Using full-sized anamorphics, particularly if you move up to 5 or 6 element designs should yield superiour results. Depending on the EF of your prime lens, close coupling may be required to use a full-sized anamorphic.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 07-30-2017 04:43 PM                     quote: Richard May I then unscrewed the anamorphic and held it an inch or 2 away from the lens and it focused fine. Would I normally need a spacer for this? You are not using "enough" of the anamorphic glass for it to work properly. Moving the lens out from the prime puts the anamorphic into a cone of light that's spread out more and that allows the anamorphic to work properly. Ideally, you want to be using 2/3 of the glass area of the anamorphic. So a proper spacer will likely cure this issue. But also what Steve said. Those old schneider lenses are not that great and full of chromatic aberration. Mark  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.