vickko Posted January 9, 2011 Share #1 Â Posted January 9, 2011 Advertisement (gone after registration) Is the optical formula for ROM vs 3-cam 2x APO extender identical? Â I see that the 3-cam version is about one-half the price of the ROM version of the 2x APO Extender. Â If the optical formulas are the same, I don't see any justification to buy the ROM one. Â Comments? Â Vick Link to post Share on other sites More sharing options...
wildlightphoto Posted January 9, 2011 Share #2 Â Posted January 9, 2011 The optical formula is the same for ROM and non-ROM as long as the non-ROM is the APO model. The non-ROM isn't 3-cam, it's R only (but can be modified to fit the SL2, with stop-down metering). Â A non-APO 2x extender was also produced many years ago, be sure you are comparing APO ROM with APO non-ROM. Link to post Share on other sites More sharing options...
masjah Posted January 9, 2011 Share #3 Â Posted January 9, 2011 Informed opinion is that the non-APO extender is simply not in the same league as the later APO one (whether R cam or ROM). It's likely that the much cheaper one you have seen is the earlier non-APO version. Â If you have an R8 or R9 the ROM version is definitely worthwhile; the chip in this case is actually a small microprocessor which talks both to the lens on one side and the camera on the other. It sends the "correct" aperture to the camera. Thus, if you set the aperture to f/8 on the lens, the camera viewfinder display will show f/22. Link to post Share on other sites More sharing options...
masjah Posted January 9, 2011 Share #4  Posted January 9, 2011 Informed opinion is that the non-APO extender is simply not in the same league as the later APO one (whether R cam or ROM). It's likely that the much cheaper one you have seen is the earlier non-APO version. If you have an R8 or R9 the ROM version is definitely worthwhile; the chip in this case is actually a small microprocessor which talks both to the lens on one side and the camera on the other. It sends the "correct" aperture to the camera. Thus, if you set the aperture to f/8 on the lens, the camera viewfinder display will show f/22.  Ooops, f/16! Link to post Share on other sites More sharing options...
farnz Posted January 9, 2011 Share #5 Â Posted January 9, 2011 Informed opinion is that the non-APO extender is simply not in the same league as the later APO one (whether R cam or ROM). .... I'll second that. When I upgraded from non-APO extender to APO the performance was significant even with non-APO lenses. (...and I'm not for a moment pretending to be "informed opinion".) Â Pete. Link to post Share on other sites More sharing options...
wildlightphoto Posted January 9, 2011 Share #6 Â Posted January 9, 2011 If you have an R8 or R9 the ROM version is definitely worthwhile; the chip in this case is actually a small microprocessor which talks both to the lens on one side and the camera on the other. It sends the "correct" aperture to the camera. Thus, if you set the aperture to f/8 on the lens, the camera viewfinder display will show f/16. Â I don't see any aperture information in the viewfinder when I combine the 180mm APO-Elmarit-R (ROM) and 2x APO (ROM) Link to post Share on other sites More sharing options...
masjah Posted January 9, 2011 Share #7 Â Posted January 9, 2011 Advertisement (gone after registration) I don't see any aperture information in the viewfinder when I combine the 180mm APO-Elmarit-R (ROM) and 2x APO (ROM) Â Oh dear! I've also just put the 2xAPO (ROM) extender, followed by the 180 APO Elmarit-R (ROM), on my R8, and ti works for me; f/22 set on the lens, in A or M mode, reads f/45 in the viewfinder display. Likewise f/11 on the lens reads f/22 and f/16 reads f/32. Â I've seen there is a display problem with a non-ROM lens, and a ROM extender. The camera sees the extender ROM chip, and so expects the aperture information from the extender, but the extender can't give it, because its chip isn't getting any electronic information from the lens side. In this case, it doesn't seem to default back to mechanical information. But with a ROM lens, a ROM extender, and an R8/9 in A or M mode, it should be OK. Link to post Share on other sites More sharing options...
vickko Posted January 10, 2011 Author Share #8 Â Posted January 10, 2011 Hmmm.. I just bought a ROM 2x APO extender. But I own both ROM and 3-cam lenses. Â I hope the extender works properly with both types of lenses, ROM and 3-cam. Â And I have an R9 as well as R6.2/R7/R5. Â Is there any official literature from Leica, regarding using the ROM 2x APO-extender with 3-cam lenses? Â Vick Link to post Share on other sites More sharing options...
wildlightphoto Posted January 10, 2011 Share #9 Â Posted January 10, 2011 I hope the extender works properly with both types of lenses, ROM and 3-cam. Â I use the ROM 2x APO Extender most often with the 280mm f/4 APO, which is 3-cam. The aperture display in the viewfinder is blank but exposure metering is fine. Â I also tried the 1.4x APO extender (not ROM) and I get an approximately accurate aperture readout in the viewfinder with either R8. Whatever combinations I try the exposures are accurate. Link to post Share on other sites More sharing options...
vickko Posted January 10, 2011 Author Share #10 Â Posted January 10, 2011 That's good to hear, Doug. Thank you Link to post Share on other sites More sharing options...
masjah Posted January 10, 2011 Share #11  Posted January 10, 2011 I use the ROM 2x APO Extender most often with the 280mm f/4 APO, which is 3-cam. The aperture display in the viewfinder is blank but exposure metering is fine. I also tried the 1.4x APO extender (not ROM) and I get an approximately accurate aperture readout in the viewfinder with either R8. Whatever combinations I try the exposures are accurate.  That's my experience of an R (or 3) cam lens with my 2x ROM APO extender. No v/f aperture display, but correct exposure. In A mode, you can see the shutter speed change as you change the aperture on the lens. In M mode, you can see the bar graph change as you do the same.  Doug, thinking about diagnosing your anomaly, have you got another ROM lens you can try on your extender? My thinking is that if you simply try your 180.2.8 APO directly on the camera, without extender, and the aperture info comes up OK, it doesn't necessarily mean its ROM chip is OK - it might be dead, and thereby fooling the camera into thinking it's got a non ROM lens on, in which case the camera might get the aperture info mechanically. Link to post Share on other sites More sharing options...
wildlightphoto Posted January 10, 2011 Share #12 Â Posted January 10, 2011 Doug, thinking about diagnosing your anomaly, have you got another ROM lens you can try on your extender? Â I have only one ROM lens. Using the lens directly on the R8 I see the correct aperture information in the viewfinder, so the problem is probably in the extender. Not a major problem for me. Link to post Share on other sites More sharing options...
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