Thanks for the reply on color meters recently.I'm considering to purchase macro lens for my SINAR 4x5. but cannot decide to go for SINAR lens MACRO SINARON 180(from Rodenstock) or Rodenstock APO MACRO SIRONAR 180 (technical specification are the same but for SINAR without 'APO' in their specs ) Can anyone confirm if SINAR is also APO lens. OR I just forget these two lens and go for SINARON SE lenses for my close up job.For my close up job the average size is between 5 to 15 mm .Your advise and suggestion is very much appreciated Rgds

-- Norhisham Abu (hesham@first.net.my), February 15, 2001

Answers

Response to MACRO SINARON 180 OR APO MACRO SIRONAR 180

I can't really advise you whether there's any difference between the two 180mm lenses, but I would advise you to get neither.
Unless you have a mile of bellows extension, both these lenses are far too long for the subject sizes you've quoted. You're looking at a minimum 8:1 magnification, and about 1.5 metres of bellows extension! The maximum effective aperture would be f/45.
A 55mm macro lens, as sold for 35mm work, or a 50 mm enlarging lens used in reverse would be more suitable, and cheaper. You could use a T mount screwed into a panel to mount a 35mm camera lens. Focusing aperture will still be around f/22 with a nominal f/2.8 lens. Get a side order of light.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 15, 2001.

I suspect the two lenses are just the same. Rodenstock OEM lenses has been the subject previous threads. I'd just ask Sinar to confirm.

-- Q.-Tuan Luong (qtl@ai.sri.com), February 15, 2001.

How much magnification are you trying to achieve? How much bellows do you have? The 120mm AM Nikkor might be a better choice if you are trying to get much greater than a 1:1 magnification reproduction (on film) with reasonable bellow length.

-- Ellis Vener (evphoto@insync.net), February 15, 2001.

Or the 120mm 5.6 Rodenstock Apo Macro Sironar.

Rodenstock currently has 3 macro lenses.

120mm 5.6 Apo Macro Sironar 180mm 5.6 Apo Macro Sironar

and the 180mm 5.6 Apo Macro Digital

-- Bob Salomon (bobsalomon@mindspring.com), February 15, 2001.

Do we correctly understand that you wish to photograph objects of size 5 to 15 mm to 4x5 film, implying magnifications of about X5 to X15? Is so, you will probably want to use a shorter focal length than 180 mm, because the required bellows extensions are from 1 to 3 meters.

For greater than lifesize images with large-format cameras, a convenient and reasonable-cost approach is to use enlarging lenses. Just remember that enlarging lenses are designed to have the larger object, normally the print, on one side, and the smaller object, normally the negative, on the other. Maintain that size relationship when you switch to object and film, reversing the lens from its normal orientation when the object is smaller than the film, i.e., magnification greater than one. In this situation choose the enlarging lens based upon the object size. For example, your object size 5 to 15 mm is smaller than a 35 mm negative and so any enlarging lens normally used for making prints from 35 mm negatives would work.

Schneider (probably others) makes an adapter between the 39 mm threads of most enlarging lenses and the front threads of a #1 shutter. This allows you to use an enlarging lens in its normal orientation. To reverse it for high magnifications, Rodenstock and Nikon (and probably others) make adapters that convert the 40.5 mm front filter threads to the 39 mm thread. Using both adapters you can mount enlarging lenses with 40.5 mm filter thread in reverse orientation to a #1 shutter. If you already have a suitable enlarging lens, this is MUCH cheaper than buying a new lens and works very well.

In-camera magnifications of X5 or more are rather challenging. The depth-of-field is extremely small and so everything must be very well aligned. Exposures tend to be very long. One could do without a shutter and just use the lens cap. Don't forget to calculate the exposure increase needed because of the bellows extension.

-- Michael Briggs (michaelbriggs@earthlink.net), February 18, 2001.