Archived posting to the Leica Users Group, 2000/04/16

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Subject: [Leica] ROM lenses
From: "Robert Rose" <>
Date: Sun, 16 Apr 2000 09:57:06 -0700


I echo Ted's comments.  I have even gone to the extent of looking at the patents.

Here are my answers to your questions.

<What are the advantages of using ROM lenses?>
Right now, the only advantage that I have confirmed is when using a Metz head having motorized zoom such as the 40MZ-3 with a SCA 3501 adapter.  Let's say you last used the Metz with a long lens and now mount a 35mm.  Bingo, the head zooms back.  Or, let's say you mount a 35-70 or 28-70 zoom.  As the lens zooms the flash head zooms.  Very cool.

A close reading of the Leica literature and patents suggests that the ROM can contain other information such as MTF data that can be taken into account for exposure.  For example, it might signal the processor in the R8 that this lens has light fall off at the edges, and the zone matrix metering would compensate for this.  Also, it suggests that it can dynamically signal the camera if the aperture blades do not open all the way.  I doubt all this, but have had disagreements with some other knowledgeable people on this issue.

If exposure is that critical to you, buy the new motor Ted thinks is the cat's meow, and use the bracketing function.

By the way, I have rarely had a wrongly exposed slide from the R8, using the matrix metering with both ROM and non-ROM lenses.  The meter is wonderful.

If I was buying new, I would want the ROM, on the theory that some future body will make more use of it.  Also, I am the forgetful sort and I have indeed left the zoom on the Metz in the wrong position.

<Does the ROM chip function like the one in Nikon D lenses that inputs the focused distance into the fill-in flash equation?>
No.  By the way, my brother-in-law has the N90s with all D lenses, and the SB26 (or whatever is most way cool) flash.  Using the Metz 40Mz-3 with the bounce head and the fill light and my R8 blew away the Nikon gear for the naturalness of the lighting.  Same subjects, same film.  The Leica looked like available light.  The Nikon looked like flash.  I would not trade the R8 for the Nikon for anything.

Outdoors, using the R8 with the SF20 is simplicity itself.  Set the R8 to P and the SF20 knows exactly how much light to give for fill flash.  Beautiful results.  The R8 with a Summicron 50, no winder, and an SF20 in your pocket makes a compact travel camera.  By the way, the SF20 can't zoom so the ROM is not relevant.

<I  found no mention of the ROM capability in either the Leica Program Catalogue nor the R8 brochure that I have.>
From my patent research I believe that the ROM was originally part of an auto focus effort that has not yet arrived.

<My new R8 should be arriving next week and I was wondering if it was worth it to have Leica install the ROM chip and contacts to my lenses.>
No, absolutely not.  That is unless you can't remember to reset the Metz zoom head yourself, or you have extra cash.  If the later, send it to my attention. :-)

<Have any of you had your lenses modified. At what cost?>
None.  The non-ROM lenses I use/have used include:  60 Macro, 75-200 zoom, 19 first version, and 400.  All work fine except the older 19, which makes the viewfinder light blink because it thinks the aperture is not set right.  The pictures come out fine, however.

Bob Rose