[rollei_list] Re: Rollei TLR real image size
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Fri, 23 Oct 2009 08:13:24 -0300
...and there is this interesting info in Wikipedia:
http://en.wikipedia.org/wiki/Normal_lens
Carlos
2009/10/23 CarlosMFreaza <cmfreaza@xxxxxxxxx>:
> To add more info about the true Rollei TLR image size, the Prochnow's
> Rollei Report 2, 2001 edition, page 23-491 shows the different
> diagrams formats via the masks; for the original image format says:
> "6 x 6 cm 2 1/4 x 2 1/4" (this is the nominal format), the square
> diagram width and height has the numbers "56" and "56", this data
> coincides again with my measurements, 56x56mm; 5,6 x5,6cm.
>
> Carlos
>
>
>>This is from B&H NYC Rolleiflex 2.8 GX features:
>
>>" The Rolleiflex has a square 56 x 56mm image format capturing just 12
>>frames on 120 film. Handling is simple; two dials near the lens do
>>the adjustments of shutter speeds and apertures, and there is a focus
>>knob, wind knob, and shutter button on the sides."
>
> http://www.bhphotovideo.com/c/product/223642-USA/Rollei_10718_Rolleiflex_2_8_GX_Twin.html#features
>
>>It coincides with my measurements.
>
>>Carlos
>
> 2009/10/22 CarlosMFreaza <cmfreaza@xxxxxxxxx>:
>
> - Ocultar texto citado -
>> there is a mix about two different measurement systems, I have
>> measured true negatives and slides using the same metric decimal
>> system, the size is 56x56mm, some negs has slight variations from 56mm
>> to 56.5mm (I think the film paper back has to do with these slight
>> variations) changing the diagonal from about 79 to 79.4 mm, my 220
>> negs have 56x56mm exactly. Rollei literature says 56x56mm and 79.2mm
>> for the diagonal according the Pytagoras theorem. 2 1/4 x 2 1/4 inches
>> are 57.15mm x 57.15mm and then slightly bigger than the real frame
>> size on the roll according my measurements.
>>
>> Carlos
>>
>>
>> 2009/10/22 Richard Knoppow <dickburk@xxxxxxxxxxxxx>:
>>>
>>> ----- Original Message ----- From: "Eric Goldstein" <egoldste@xxxxxxxxx>
>>> To: <rollei_list@xxxxxxxxxxxxx>
>>> Sent: Thursday, October 22, 2009 5:24 PM
>>> Subject: [rollei_list] Re: OT:Walter Voss Diax cameras
>>>
>>>
>>> 83 mm is the diagonal for 2-1/4 square.
>>>
>>> I also read somewhere in the deep dark past that the f/2.8 lenses for
>>> the Rollei TLRs were taken from 75 to 80mm because the slightly longer
>>> lenses would be easier to correct as faster optics. It is reasonable
>>> to assume that this was the case, as it makes sense from a design POV.
>>>
>>>
>>> Eric Goldstein
>>>
>>> Exactly what I said:-)
>>> I measured a couple of Rollei negatives (also a Rolleicord IV film gate)
>>> and found they were exactly 2-1/4 x 2-1/4 so the calculated diagonal comes
>>> out about 81 mm. If you use 6x6 cm it will come out nearly 85 mm but that is
>>> not the size of the actual negatives.
>>> There are cases where the "nominal" film size is not the actual film size.
>>> This is especially the case for sheet film of 4x5 and larger. The film is
>>> smaller. I think this may be due to the film being intended for use in plate
>>> holders with adaptor sheaths but that would not explain why smaller sizes
>>> are the same for nominal and actual. Perhaps its because they came along
>>> later in the history of film. I think glass plates are actually the nominal
>>> size but have none to measure.
>>> The difference is significant, for instance the calculated diagonal of
>>> 4x5" is 6.4 inches (about 163 mm) while the actual image diagonal is only
>>> about 152 mm.
>
---
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