Ikonta A lens and dual format question

[pb908]

I have seen that in ikonta A (6x4.5, whatever the series/years) that they use 75mm lens. Is this lens is the same as the one use on 6x6 model? What I want is to replace the novar on my mess ikonta with 75mm/80mm tessar, but tessar on 6x6 body cost me a lot, while the one in Ikonta A doesn't. If they are actually the same lens/coverage, i think i'll start to hunts for it.

regarding dual format, if I have a mask for 645 on 6x9 body with 105mm lens, what fov equivalent of the lens will be?
will 6x6 croped image from 6x9 camera have the same fov as the 6x6 of 6x6 camera? I don't think so.
I was thinking that having 6x9/6x6 dual format is a good reason to discard 6x6 body, but if the 6x6 crop out of 6x9 body is not the same as 6x6 out from 6x6 body, what is the point of having dual format? Just to crop and add more frame? I don't get the idea,please advice.

 

[pb908]

ideal focal length for portrait ?
Chippy, if I'm not wrong, by croping 645 out of 6x9, we only take the central part of the image, which is not the same as change the FL of the lens to a portrait lens.

this is the same effect I get from using aps-c (1.5x crop) DSLR and 50mm full frame lens, that in the end I think like I am using 75mm (50mm x 1.5) lens but actually it has the same 50mm properties(dof, etc).

so at any point, having dual format doesn't mean the same as having one each of every format (6x9, 6x6, 645) ? well, then I need to really have them all to see which one is the ONE i need/use most, as I can not equalize the feel and the result of them with having a single 6x9 + dual/triple format mask. how about you chippy?

after seeing the result of bessa II with skopar, I feel that i found a gem ! the novar i got before is nothing compare to skopar. that's why I try to find an an answer about "do i need this 6x6" or "can I use 6x9 with mask to replace this", before I let it go for good.

 

[pb908]

as you said that the lens in 6x4.5 is the same as lens in 6x6, so technically 6x6 will have more benefit as it has more angle of coverage in both horizontal & vertical. pictures made from 6x4.5 can be made from a crop of 6x6, so there are no "benefit" of 6x4.5 camera other than it being smaller (6x6 with mask can do the same frames as 6x4.5), am i right ?

so then, would it be ideal to have both 6x6 and 6x9 ( as well with mask for 6x4.5 in both format), so we have option to make 6x4.5 normal, 6x4.5 portrait, 6x6, and 6x9 😀