Some general info regarding MF lenses and film sizes


nightwolf75

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Dec 18, 2003
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#1
i went to dig ard for this info for future MF users' reference. this started becos some CS asked for such info in one of my query threads here. hope its of help! ;)

got this info from another website. the guy hasn't updated it. so i hope the info is still relevant.


Focal length

28mm (in 35mm) = 45mm (in 6x4.5) = 45mm (in 6x6) = 60mm (in 6x7)
50mm (in 35mm) = 80mm (in 6x4.5) = 80mm (in 6x6) = 110mm (in 6x7)
105mm (in 35mm) = 180mm (in 6x4.5) = 180mm (in 6x6) = 210mm (in 6x7)
200mm (in 35mm ) = 350mm (in 6x4.5) = 350mm (in 6x6) = 500mm (in 6x7)

Camera Formats - obtained from luminous-landscape.com

6 X 4.5 cm
This is a rectangle that is very close in proportion to the 8X10" print format and will enlarge to this format with very little cropping needed. The most popular cameras in this size are the Mamiya 645, the Pentax 645, Bronica 645 and the Contax 645. These cameras are the most like 35mm cameras in size and handling. Most now offer autofocus and extensive automation. They are the smallest SLRs that use roll film. 645 cameras get 15 or 16 frames to a roll of 120 film.

6 X 6 cm
6X6 is the most popular roll film format. Why is this? Part of the reason is that this square contains both a vertical and a horizontal composition on the same frame. A 6X6 image is composed of a vertical 6X4.5 and a horizontal 6X4.5. No need to rotate the camera. No need to rotate the film back. Just take one shot and get both compositions. Some people, myself included, also find a square image very appropriate for some subjects. One gets 12 frames to a roll of 120. 6X6 cameras give 12 exposures from 120 film.

6 X 7 cm
6X7 is very popular for several reasons. Like 645 the format it enlarges to an 8X10" print with little cropping. Though only slightly larger than 6X6. There are four popular cameras offering this format; the Mamiya 7II, the Pentax 67II and the Mamiya RB & RZ67. The Bronica GS1 is also a contender. One gets 10 frames to a roll of 120 with this format, and either 20 or 21 frames on 220 film, depending on the camera.

a website on info for MF cameras - http://medfmt.8k.com/mf/ do note - most of the stuff hasn't been updated in a while... then again, most MF cam film models hasn't been updated too! :)
 

nightwolf75

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Dec 18, 2003
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#2
eh.... wonder how come blurblock's comments were lost... :think:

anyway, thanks blurblock for pointing out the errors! have u mentioned that the format sizes were wrong, i went to double-check on luminous-landscape and copied out some info from there to update the thread. thanks! ;)
 

blurblock

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#3
A bit off course ..... a rough estimation is this :-

6 x 4.5 = (X) / 0.66 * Where X = 35mm lens size
6 x 6 = (X) / 0.62
6 x 7 = (X) / 0.45

But in actual fact, it is very much more complex then that :),

Makes the ratio aspect based on Diagonal 4:5 (we should take it as when one take in Medium format, one will want at least a 8 x 10 sized picture, thus the 4 : 5 ratio, anyway, as the size grow larger, the ratio aspect become more square, 3:5, 4:6, 5:7, 6:8, 7:9, 8:10.... etc etc) (with relevancy to 35mm) :

6 x 4.5 - 1.73(X) * Where X = 35mm size
6 x 6 - 1.84(X)
6 x 7 - 2.27 (X)
6 x 9 - 2.29 (X)
4 x 5 (in) - 4(X) (From here onwards, large format)
5 x 7 (in) - 5(X)
8 x 10(in) - 8(X)
11x14(in) - 11.5(X)

However in actual fact the effectively space based on the Diagonal cut of the entire images :-

6 x 4.5 - 1.61(X) * Where X = 35mm size
6 x 6 - 1.8(X)
6 x 7 - 2.02 (X)
6 x 9 - 2.35 (X)
4 x 5 (in) - 3.55(X) (From here onwards, large format)
5 x 7 (in) - 4.81(X)
8 x 10(in) - 7.21(X)
11x14(in) - 10.34(X)

(Now you know why different manufacturers have different ratio aspect :) .... even though the films size are the same :D )

Thus in 8 x 10 (ratio 0.8) size 6 x 4.5 (ratio 0.75) and 6 x 7 (ratio 0.85) have absolute advantage over 6 x 6 (ratio 1.0) as both 6 x 4.5 and 6 x 7 will have less wastage of spaces.

At 22 x 24 (ratio 0.92) size 6 x 4.5 (0.75) will lose out a bit, 6 x 7 (0.85) and 6 x 6 (1.0) will be better .... but quality wise 6 x 7 will have slightly better output then 6 x 6 .... due to the fact ...... Bigger film size :D .
 

blurblock

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#4
nightwolf75 said:
eh.... wonder how come blurblock's comments were lost... :think:

anyway, thanks blurblock for pointing out the errors! have u mentioned that the format sizes were wrong, i went to double-check on luminous-landscape and copied out some info from there to update the thread. thanks! ;)

Sorry, me do a more detail list :) .... hehehehe .... a bit KPO, so got to do some calculation first before sending it up :)
 

nightwolf75

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Staff member
Dec 18, 2003
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#5
oic! i also din know the answers until i go and scout ard. a number of MF websites out there are quite outdated (as we have seen! :bsmilie: ) the lens measurements were from another website's table. so, i thot it was a useful guide for MF newbies like me when trying to figure out the lens! :embrass:

now, if only the mods will make this a sticky... :think:
 

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