[rollei_list] Re: 3.5 Tessar sharpness

  • From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
  • To: <rollei_list@xxxxxxxxxxxxx>
  • Date: Fri, 23 Dec 2005 14:41:42 -0800


----- Original Message ----- From: "James Davis" <jamesd@xxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx>
Sent: Friday, December 23, 2005 12:47 PM
Subject: [rollei_list] 3.5 Tessar sharpness


What range of apertures produces optimum sharpness on a f/3.5 Tessar as
found on a 'flex T?

James

The best range is around f/8 to f/16. Rollei limits the stops to f/22 to avoid softening from diffraction at smaller stops. Optimum is probably around f/11 but anything from f/8 on should be pretty sharp all over. The difference from stopping down will be most apparent in the corners. Tessars of any version have some residual aberrations there which disappear on stopping down.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx


---
Rollei List

- Post to rollei_list@xxxxxxxxxxxxx

- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org

- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org

- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list

Other related posts:

  1. Home
  2. rollei_list
  3. Archive
  4. 12-2005