[rollei_list] Re: Rollei B&W filters blog
- From: CarlosMFreaza <cmfreaza@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Mon, 1 Aug 2011 16:29:12 -0300
Larry:
The SL 66 "Bible" (The Rolleiflex SL 66 and SLX Way by L.
Andrew Mannheim) talks about the SL 66 Infrared filter in the page
328, the transmission is from 750 nm (from 700nm for the compensated
TLR IR filter and from 720nm for the R72 Hoya IR filter). The book
says "...A focusing correction is required with all lenses _other than
the 250mm Sonnar Superachromat_..." . This book explains how to use
the SL 66 focusing knob DOF marks to compensate the focus shift with a
dedicated table on the page 585, the table has scales for 720nm (deep
red Rollei filter) with infrared film and 840nm when using the
infrared Rollei filter.
Carlos
2011/8/1 Laurence Segil <ljsegil@xxxxxxx>:
> Thanks Carlos!
> Larry
>
> On Mon, Aug 1, 2011 at 9:08 AM, CarlosMFreaza <cmfreaza@xxxxxxxxx> wrote:
>>
>> The Rollei Infrarot filter with optical compensation was only made for
>> the TLR from 1951 to 1981 (BI; from 1952 for BIII and from 1956 for
>> BII ). A IR filter with optical compensation does not make sense for a
>> SLR since, as you wrote, it's impossible to focus and to compose with
>> an IR filter, they are called "black" filters. Rollei TLR cameras
>> lenses never had HFT or multi-coating during the F&H and Rollei
>> Werke/F&H era regular production, the number and size of the lenses
>> elements did not justify this expensive process (at the beginning
>> specially); when the Rollei IR filter with optical compensation was
>> designed, Rollei TLR lenses already had the single layer coating.
>> I really think HFT lens multicoating can not affect the Rollei IR
>> optical compensation since regular MC processes are made to cancel
>> reflections from the main visible spectrum rays (400-700nm being about
>> 550nm the main wavelenght chosen for single and multi layer lens
>> coating), at least they are not made for the infrared, beyond regular
>> wavelengths; if a lens has a coating and optical correction for IR
>> rays made from special material, it wouldn't be an issue for the
>> filter since they are in the same wavelength, but it would be
>> redundant. The way to know for sure if the HFT multicoating could
>> affect the Rollei TLR IR filter with optical compensation performance
>> would be to use it in a 2.8F Platin or newer TLR models with HFT MC, I
>> never read about a problem with the Rollei TLR IR filter and lens
>> multicoating and I'm pretty sure it couldn't happen.
>>
>> The SL 66 camera has means to compensate the IR photography focus
>> shift in the focusing knob, it requires to focus wothout the IR filter
>> of course. The more significant lenses manufacturers produced and
>> produce expensive lenses for SLR cameras with optical correction for
>> five or six light wavelengths including IR, f.e. the Carl Zeiss
>> Sonnar 5.6/250 Superachromat for Rollei SL 66 and Hasselblad, I recall
>> a Nikon lens too, these lenses can be focus for IR directly without
>> focus shift compensation.-
>>
>> Carlos
>>
>>
>>
>> 2011/8/1 Laurence Segil <ljsegil@xxxxxxx>:
>> > How well do the lenses with HFT coating pass IR wavelength light? Does
>> > the
>> > multicoating filter out the longer wavelengths? I am thinking here of
>> > the
>> > newer SL66 lenses in particular. Would the modern Rollei infrarot
>> > filter
>> > also serve for IR focus correction on the SL66? It seems to me that if
>> > it
>> > does so on a TLR, then the same ought to be true on the SLR if focus is
>> > achieved prior to placement of the filter. I have not found it possible
>> > to
>> > view any image on the ground glass of the SL66 (a Maxwell screen on my
>> > camera) with the IR filter in place, it is simply too dark to compose or
>> > focus (or even imagine what the lens might be pointed at). All of the
>> > collective expertise of the forum is appreciated.
>> > Best,
>> > Larry
>> >
>> > On Mon, Aug 1, 2011 at 12:44 AM, hari ho <hariho@xxxxxxxxxxxxxxx> wrote:
>> >>
>> >> Thanks Carlos.
>> >>
>> >> Hari
>> >>
>> >>
>> >>
>> >>
>> >> On 30/07/2011, at 7:21 PM, CarlosMFreaza wrote:
>> >>
>> >>> 2011/7/30 hari ho <hariho@xxxxxxxxxxxxxxx>:
>> >>>>
>> >>>> .... How can I tell if my Infrarot filter is post-1951? The markings
>> >>>> on
>> >>>> the front says
>> >>>> "FRANKE & HEIDECKE GERMANY Rollei - Infrarot" in black with the
>> >>>> Rollei
>> >>>> 'R' logo in red.
>> >>>
>> >>> According W D Emanuel book on the Rolleiflex, if your filter has the
>> >>> "R", it is provided with the IR optical compensation. The red for the
>> >>> "R" could indicate your filter is from the earlier '50s.
>> >>> Carlos
>> >>> ---
>> >>> Rollei List
>> >>>
>> >>> - Post to rollei_list@xxxxxxxxxxxxx
>> >>>
>> >>> - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
>> >>> in the subject field OR by logging into www.freelists.org
>> >>>
>> >>> - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
>> >>> 'unsubscribe' in the subject field OR by logging into
>> >>> www.freelists.org
>> >>>
>> >>> - Online, searchable archives are available at
>> >>> //www.freelists.org/archives/rollei_list
>> >>>
>> >>>
>> >>
>> >> ---
>> >> Rollei List
>> >>
>> >> - Post to rollei_list@xxxxxxxxxxxxx
>> >>
>> >> - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'in the
>> >> subject field OR by logging into www.freelists.org
>> >>
>> >> - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with'unsubscribe' in
>> >> the subject field OR by logging into www.freelists.org
>> >>
>> >> - Online, searchable archives are available at
>> >> //www.freelists.org/archives/rollei_list
>> >>
>> >
>> >
>> ---
>> Rollei List
>>
>> - Post to rollei_list@xxxxxxxxxxxxx
>>
>> - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
>> in the subject field OR by logging into www.freelists.org
>>
>> - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
>> 'unsubscribe' in the subject field OR by logging into www.freelists.org
>>
>> - Online, searchable archives are available at
>> //www.freelists.org/archives/rollei_list
>>
>
>
---
Rollei List
- Post to rollei_list@xxxxxxxxxxxxx
- Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe'
in the subject field OR by logging into www.freelists.org
- Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with
'unsubscribe' in the subject field OR by logging into www.freelists.org
- Online, searchable archives are available at
//www.freelists.org/archives/rollei_list
Other related posts:
