mellow13
Newbie
Hi all. I just got into the RF world not too long ago. I've been trying to learn as much as I can here on the forums and I picked up a used Ikon with a Biogon 28/2.8 lens awhile back so I could join in on the fun. 
It's been a great experience so far, but I just started noticing something today.
When focusing down on a close subject, the secondary patch moves as expected until about 0.6m. Then between the 0.6m to 0.5m range (closest focusing distance marked on the biogon), the secondary image in the viewfinder no longer moves. I haven't developed the roll yet, so I'm not sure how it's translating to the final image.
I tried my old Summar lens on to check if it would behave the same way but the secondary image seems to move smoothly as expected throughout the entire focal range. However, the Summar does only focus down to 1m. I'll test my CV 35/1.4 when I get home tomorrow.
If there's any other info I can provide to clarify the situation, I'll do my best to provide it. Thank you.
It's been a great experience so far, but I just started noticing something today. When focusing down on a close subject, the secondary patch moves as expected until about 0.6m. Then between the 0.6m to 0.5m range (closest focusing distance marked on the biogon), the secondary image in the viewfinder no longer moves. I haven't developed the roll yet, so I'm not sure how it's translating to the final image.
I tried my old Summar lens on to check if it would behave the same way but the secondary image seems to move smoothly as expected throughout the entire focal range. However, the Summar does only focus down to 1m. I'll test my CV 35/1.4 when I get home tomorrow.
If there's any other info I can provide to clarify the situation, I'll do my best to provide it. Thank you.
Perfectly normal. The focus patch is coupled down to about 0.65 - 0.70m, but the 28 Biogon will focus down to 0.50m. Once you focus under 0.65m - 0.70m the rangefinder disengages.
mikeong
Member
Yep, that's the minimum distance you'll get coupled focusing unless the camera is modified to focus closer. Though I'm not sure if its possible to modify any modern RF cameras like the Zeiss Ikon and various Bessas.
Older Leicas (M3, M2 I think?) are only coupled down to about 0.90m, but can be modified to couple closer.
mikeong
Member
Thanks a lot Jonmanhiro. What about for newer Ms? FSUs?
I think the min. coupled focus distance of the newer M's is the same as the Zeiss Ikon and Bessas. Not sure if they can be modified. No experience with FSU cameras.
mikeong
Member
payasam
a.k.a. Mukul Dube
Focussing closer than 60cm with a 28mm lens is unusual, mellow13, and perhaps a bit dangerous also. Welcome to RFF.
Juan Valdenebro
Truth is beauty
Don't tell that to the great Bruce Gilden or his fan club!
I'm sorry, it was very tempting...
Cheers,
Juan