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CFV50C and 903 SWC?

Grayhand

Well-known member
:thumbs: Ray!
I remember the original compared at around a 21mm on the 24x36mm format, horisontalwise, but actually perhaps more like a 24-25mm, as it is 72 degree horisontal.
As the cropfactor is 1,45, where do you then end?, like a 28mm or more in the horisontalview in 35 format?
thorkil
If we say that the viewing angle of the 38 is about 90 degrees with a film back, then it should be roughly 70 degree with the CFV50C (Horizontal)

Then I leave the rest of the math to you :)

Ray
 

Thorkil

Well-known member
If we say that the viewing angle of the 38 is about 90 degrees with a film back, then it should be roughly 70 degree with the CFV50C (Horizontal)

Then I leave the rest of the math to you :)

Ray
ha-ha...I was beginning to get headache, trying to calculate... :)
best Thorkil
 

Godfrey

Well-known member
ha-ha...I was beginning to get headache, trying to calculate... :)
best Thorkil
"Rui Salgueiro's field-of-view calculator" is your friend...
Rui Salgueiro's field-of-view calculator

Hasselblad SWC on film

Query Results

You submitted the following name/value pairs:
focal = 38
format = 56 56
Width = 56 mm, Length = 56 mm, Diagonal = 79.196 mm
f Hor Vert Diag H/V
38.0 72.7687 72.7687 92.3595 1.0000​


Hasselblad SWC - Biogon 38mm lens on CFV-50c

Query Results

You submitted the following name/value pairs:
focal = 38
format = other
width = 33
length = 44
Width = 33 mm, Length = 44 mm, Diagonal = 55 mm
f Hor Vert Diag H/V
38.0 60.1372 46.9420 71.7853 1.2811​


Typical range of 35mm FF focal lengths

Query Results

You submitted the following name/value pairs:
focal = 24 28 35 50 75 85 90
format = 24 36
Width = 24 mm, Length = 36 mm, Diagonal = 43.2666 mm
f Hor Vert Diag H/V
24.0 73.7398 53.1301 84.0622 1.3879
28.0 65.4705 46.3972 75.3806 1.4111
35.0 54.4322 37.8493 63.4400 1.4381
50.0 39.5978 26.9915 46.7930 1.4670
75.0 26.9915 18.1806 32.1798 1.4846
85.0 23.9132 16.0714 28.5583 1.4879
90.0 22.6199 15.1893 27.0316 1.4892​

Looks to be about the equivalent of a 30mm focal length on FF 35mm format by the diagonal, but of course the format proportions are different.

enjoy,
G
 

Thorkil

Well-known member
Perhaps a simpel short-cut to avoid deadache could be this.
The SWC with film inside is said to have a horisontal viewangle of 72.
A Carl Zeiss 25mm lens on 24x26 format is said to have an horisontal viewangle of 71.
So horisontalwise the SWC with film must be about a 25mm.
I guess the cropfactor of the CFV50C which is claimed to be 1,45 means that the focal length should be 1,45 x 25mm = 36mm.
Does this look like being right?
Thorkil
 

Thorkil

Well-known member
Godfrey, if I do understand your figures correct, then I'm wrong and the focal length should be in the middle between 28 and 35mm, around 32mm?
best Thorkil
 

Grayhand

Well-known member
It is always nice to realise that I am wrong :D

But I do hate the diagonal equivalence comparing between different formats..

I think horizontal but the 90 degree I was using is the diagonal.
It is about 70 degree diagonally for the digiback.

So if 72.8 degree horizontal with a film back, then it should be around 57 degrees with a CFV 50C back?
Not sure where the 60.1 in Godfrey`s data run did come from?
But there is a lot that I am not sure about :cool:

But; I am sure that no one is looking diagonally at the world...

Ray
 

Godfrey

Well-known member
Equivalences between unlike format proportions are always problematic because the format proportions lend a lot of the 'feel' to a photo. It's customary to use the diagonal for various reasons, but often a little misleading; for example, diagonal AoV of the Biogon 38mm on 6x6 is quite close to 21mm on FF35, but because of the square nature of the 6x6 proportion, it always LOOKS significantly wider.

The calculation is based on three formats: 120 6x6cm == 56x56 mm (1:1 format), CVF-50c == 33x44mm (3:4 format), and FF35 == 24x36mm (2:3 format).

So rather than look at the diagonal, look at the horizontal AoV calculations rounded to nearest whole degree:

Biogon 38mm:
Format 6x6: 78°
Format 33x44: 60°​

Equivalence on FF35 using the horizontal AoV is thus about 24mm for 6x6 format and about 31-30mm for 33x44 format.

It's not precise but it's close enough. :D

That tells you about what your horizontal coverage is, but doesn't do a good job of giving you the feel of the coverage on the different formats. It's why I tend to avoid using equivalences. I'd rather just learn what each format does with different field of views. I use focal length equivalences to determine about what focal length lens I might need for a different format camera, but after that I no longer really think in equivalences: I just learn what the lenses I bought do and try to take advantage of it.

G
 

ChrisLivsey

New member
Because I have still not recieved the 90 degree adapter I ordered close to two months ago now. And when the back is discontinued, who knows?
SNIP
HB wants about 300 USD for the adapter, that is if they ever will ship it..

Ray
A quick check of UK dealers shows discontinued item at two for the 3054668 part, looks like the right decision.
 

Grayhand

Well-known member
It is always irritating when some one shoot holes in your new theories.
Here I hade start to believe that the 90 degree battery adaptor had gone extinct!

Then I find this in my post when I come home after a work trip:



Two months after ordering it...

So what does this mean?
Will the next shipping be a new version of the CFV50C :shocked:
 

Grayhand

Well-known member
Regarding our discussion about how to view different sensor formats:



From 6x6 to 6x17

For me the perfect format is 6x6.
But that does not mean that I always use it because it is not always perfect regarding a specific composition...

The horizontal angle of view that I want I get by selecting the appropriate focal length.
The amount of sky possible is then limited by the sensor format that I use.

6x6 gives me the largest amount of freedom regarding the possible ways to crop the photo.
So this is why I never think diagonally when thinking about format and size!

Ray
 

Godfrey

Well-known member
Regarding our discussion about how to view different sensor formats:



From 6x6 to 6x17

For me the perfect format is 6x6.
But that does not mean that I always use it because it is not always perfect regarding a specific composition...

The horizontal angle of view that I want I get by selecting the appropriate focal length.
The amount of sky possible is then limited by the sensor format that I use.

6x6 gives me the largest amount of freedom regarding the possible ways to crop the photo.
So this is why I never think diagonally when thinking about format and size!

Ray
:D

Whatever works for you. I tend to just work with the format proportions, unless I see something that needs a different set of proportions to tickle my eye correctly. I just like square format a lot and many of my photos are organized in a way that fits the square... I like the way it presents the relationships between objects and space.

G
 

grrr101

New member
I had for some time a SWC and a CFV50c

At first I used the CFV50c connected to the computer so no battery was needed to power the CFV50c

Then I learned that the L adapter was not enough to use the CFV50c with its battery on the SWC, so I had the SWC modified professionnally so as to allow the use of the CFV50c with its battery

In all cases I found there were no problems in the images taken with the CFV50c on the SWC

Guy
 

Grayhand

Well-known member
:D

Whatever works for you. I tend to just work with the format proportions, unless I see something that needs a different set of proportions to tickle my eye correctly. I just like square format a lot and many of my photos are organized in a way that fits the square... I like the way it presents the relationships between objects and space.

G
As far as I can see, we are more or less saying the same thing:
If possible, we both prefer the square format for a composition!

So: Whatever works for you :D

Ray
 

Grayhand

Well-known member
I had for some time a SWC and a CFV50c

SNIP
Then I learned that the L adapter was not enough to use the CFV50c with its battery on the SWC, so I had the SWC modified professionnally so as to allow the use of the CFV50c with its battery

Guy
What was the problem with your SWC, was it something with the foot that you had to modify?

I have tried the adapter on my 903SWC with out any problem, except that I did not put the original foot back for this test.

Ray
 

grrr101

New member
What was the problem with your SWC, was it something with the foot that you had to modify?

I have tried the adapter on my 903SWC with out any problem, except that I did not put the original foot back for this test.

Ray
Yes, I had to (or was told I had to) cut the foot
The problem is that there is more to that than simply cutting the foot : the tricky part is to have everything precisely positioned after the foot has been cut

I can post a picture of the modified SWC if you want to

Guy
 

Grayhand

Well-known member
I think it would be helpful to see the modification that was made to the fot of your SWC.
Then I/we can see what has to be done to be able to use the batteri adapter on the SWC.

I must admit that I was a bit surprised that you had to modify your camera.
I had the impression that it was enough to use the adapter on the SWC?

Ray
 
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