Advertisements

Tag Archives: Aperture

How good is Rolleiflex 2.8C – A review in 1952

 

Modern Photography, May 1952, pg. 57-98 
The New Rollei 
How Good is the New $385 Model 2.8C Which Incorporates Suggestions Made by 
Photographers?…By Arthur Kramer 

“The New Lens” 

“The camera’s most important feature is its new 80mm, air-spaced 
five-element f/2.8 Schneider Xenotar lens. The f/2.8 lens on a previous 
model was a four-element objective which often gave trouble when used wide 
open. The makers of the Rolleiflex claim this trouble has been eliminated 
in the Xenotar lens. Optical and practical tests (which we will get to 
later) indicated that this was true – at least on the cameras tested.” 

“The Lens – How Good?” 

“Finally we get to the most important of all the improvements – the lens. 
This is not the first f/2.8 lens ever put on a 2 1/4 x 2 1/4 Rollei. Many 
photographers who have used or tested the previous f/2.8 model, which this 
new camera supersedes, felt that the definition was not up to their 
acceptable standards. Wide aperture lenses which must cover comparatively 
large film areas are often notoriously poor in edge definition at full 
aperture. Practically all Automatic Rolleiflexes have up to this time been 
supplied with four element Tessar or Xenar f/3.5 or Tessar f/2.8 lenses. 
The new Xenotar is a five-element lens of the air-spaced type. It was not 
until the advent of modern optical coatings that the full advantage of such 
a design could be exploited.” 

“Bench Testing” 

“The camera was taken to a well-equipped optical laboratory and placed on 
an optical bench. The lens appeared to be free of astigmatism. It showed no 
shift of focus when stopped down. There seemed to be the faintest trace of 
flare at f/2.8 but this disappeared when the diaphragm was stopped down to 
about f/3, a definite improvement in this respect to what we had previously 
seen in other lenses of similar focal length and aperture.” 
“The definition at the edges was far above that of the old four-element 
f/2.8. This individual Xenotar lens looked excellent in bench tests, but 
that did not guarantee excellent pictures. Only extensive tests on actual 
film could tell about that.” 

“Practical Testing” 

” The camera was also checked for lens, film, and ground glass alignment. 
Then it was ready for the film tests. An f/3.5 Rollei of known image 
quality was used as a control unit The first test was made on a cross-lit 
brick wall A series of shots was taken at various distances and apertures 
with both cameras. Negatives were carefully enlarged to about 30×30 inches 
and examined over the entire field. Results showed that the Xenotar f/2.8 
lens wide open was equal in most respects to the f/3.5 lens wide open. It 
did not noticeably lose definition when stopped down to f/22. A second 
Xenotar tested actually had better definition at f/2.8 than the older type 
lens had at f/3.5! The tests were repeated on various objects and at varied 
distances with the same result. The next test was of a more practical 
nature. Portraits of actor Jack Palance (!) were shot at full aperture with 
the camera at its closest distance, about three and one half feet (page 
59). The inset on the enlargement shows the entire negative area. The 11×14 
glossy prints were quite sharp, and had excellent image quality. Twenty 
rolls or film were used on a variety of subjects. Results were consistently 
good.” 

Advertisements

Mamiya TLR Restoration/ Repair Lessons

Read the FUll Topic

For the older photographers in our forum, that use or plan to use Mamiya TLR cameras and lenses. Here are my lessons learned from repairing a couple of used “chrome” Mamiya TLR lenses. The usual disclaimer, use the lessons learned at your own risk.

Zero, before you start handling the lenses wash your hands. Use a clean white towel on a well lighted table as your work area. Should a part or screw fall out it will not go far and can be seen.

First, do not remove the lens from the back plane frame, there is no need to access the lens from that side. Front and rear optical assemblies unscrew. There is no need to use a spanner wrench on the retaining clamps that secure the lens to the supporting frame.

Second, if the shutter will not cock the chances are a single screw has come loose within the shutter assembly that can be restored. This screw is located at the two O’clock position viewing the exposed taking lens shutter assembly straight on with upper rings and cam plate removed, viewing lens at 12 o’clock.

Third, if the shutter cocks but does not operate the blades when released a different screw is loose or has fallen out, that can be restored. This is located just south of the release lever mechanism. Check all screws for tightness.

Fourth, never use oil on any part of the shutter mechanism or ring assemblies or aperture assemblies.

Fifth, if the aperture blades mechanism is stuck or sticky, this can be cured using small amounts of 91% isopropyl rubbing alcohol applied with a damp Q-tip. To access the aperture internal assembly, This will require unscrewing the rear optical assembly. Work the mechanism manually using the aperture selector arm, do not touch the blades with your fingers and use another Q-tip to remove excess and any grime. Do not use oil. Be sure to remove any lint left behind by the Q-tips prior to reassembly.

Sixth, if the shutter ring is sticky or the clicks indents are not “sharp”, disassemble the two rings and clean them with isopropyl alcohol. Slightly bend the metal finger on the cam plate that engages the indents on the shutter selection ring.

Seventh, screws are tiny, and can be lost in a flash. For most repairs I have done only one screw has to be removed.

Eighth, acquire the proper tools, i.e. jewelers screwdrivers, needle nose tweezers, etc. A spanner wrench designed for lenses is required (see lesson 10) to remove the optical retaining rings that hold the individual elements. If you do this be sure to note on paper which side is up, in or out facing. Do not rely on your memory.

Ninth, use ROR per the instructions to clean the optics, and do not use canned air.

Tenth, use rubbing alcohol mentioned above with your finger tips (no fingernails, just skin) in a circular motion to remove fungus clouds from optical surfaces. It may require several times to completely remove the fungus. Do not allow excess to drip anywhere. Clean with a lint free, chemical free (no anti static chemicals used in the dryer), white cotton t-shirt. Then use ROR with a t-shirt to remove any residues.

So far, I have restored two Mamiya TLR chrome shutter lenses and both are working fine now. They were a lost cause when I started. They are simple in design and easy to restore.

If you have any second thoughts I recommend taking your lens to a repair facility. But if you are a risk taker and have some common mechanical sense, my lessons learned may prove useful. Search the web for other information sources, and photographs of the lens assembly.

Good luck,

d2f