Linhof holders and precision

[david_kirk1]

Can anyone give any info on these Linhof holders that I've just bought in Glasgow; They are clearly marked Linhof in the standard(?) whitw lettering, West Germany is printed in raised characters, and they have DPa and APa, the APa has on either side of the holder, an arrow pointing to a lever. Also, the little number is not stuck onto the top end of the holder, but on the hinged bottom end. But what I find most interesting is that instead of the aluminium solid sheet that the film rests on, there is a pressure plate. I paid #50 for five (although about another five currently remain with Quiggs).

Thanks for any help.

One more thing, with reference to my previous 'little help here' question, I've squared that away - I've decided to use a 6x7 roll film back if it becomes neccessary.

[wilhelm]

It sounds like you mave have holders which can also be used to hold

glass plates.

[julio_fernandez]

Unless this is a onse sided holder I believe you have the standard

holders. The lever is used to eject the film and prevents your

getting your fingers on it when you remove it. The pressure plate is

simlar to that on the graphmatic. These holders are very accurate.

Sounds like you got a good buy.

[sal_santamaura]

Julio's got it right, except that these holders are no more accurate

than any others. I researched this some years back and received,

through Linhof's US importer, a fax from the factory answering my

questions on film plane positioning and flatness. The response stated

that their holder design simply met normal standards, and claimed

that depth of focus makes anything more precise unecessary

(paraphrased from memory).

[julio_fernandez]

Sal's information from Linhof most likely refers to ISO standards.

The ANSI standard allows plus or minus 0.007" a huge variation.

Sinar and linhof have tighter standards than ANSI. The ISO standard,

according to Sinar is 4.85mm with a tolerance of plus or minus 0.05

mm. This works out to plus or minus 0.002". Linhof's holders may be

not more accurate than other ISO holders but they will certainly be

more accurate than US ANSI holders, read Lisco, etc. Sinar's holder

is guaranteed to plus or minus 0.001".

[sal_santamaura]

If you're saying that Linhof holders meet an ISO standard of 4.85mm

for septum depth, then there is another problem. That works out to

0.191" instead of the ANSI 0.197" T value for 4x5. If your camera

sets its ground glass at 0.190" to account for flim thickness of

0.007" as most do, we have an automatic discrepancy of 0.006" +/-

0.002" to begin with. In any case, Linhof was probably very

forthcoming in its response, since septum depth is only one factor

that determines emulsion position.

 

<p>

 

I know of only one way to insure ground glass and emulsion fall into

identical (for practical purposes) planes, and that is to use the

Schneider Hi End Back system. When one's work warrants this

precision, such as large aperture closeups using short focal length

lenses with the camera pointed down, only such a matched set of vacuum

camera back (with its own ground glass) and dedicated holders can

deliver. For more distant subjects using normal or longer lenses,

such as landscapes, Linhof's suggestion to rely on depth of focus

probably makes sense.

[julio_fernandez]

Sal: you are a thorough guy, good stuff but you are making me do more

work. OK.

The two standards ISO, ANSI are not exactly identical. Without film

the ANSI, holder depth, should be (0.197") 5.0038mm. The ISO holder

depth is 4.85mm. Accordingly, there is a discrepancy, ANSI being

0.1538 mm deeper. Another issue is film thickness. Most people

quote 0.007�. This is only true for color negative films: Fuji and

Kodak are (0.007") 0.1778mm. -I do not know what B&W pos or negative

film thickness are. This is not true for color transparency films.

According to my measurements, Velvia, Astia are 0.0090-0.0095" and

some old Ektachrome I measured at 0.0090"; for transparency film lets

use an average of 0.00925�, (0.235mm). Why is it that negative and

transparency films come in different thickness? I do not know and

one would expect that manufacturers would settle on one common

thickness.

 

<p>

 

When we load transparency film in the ANSI holders, holder flange to

film depth becomes 4.770mm. For ISO holders and film, subtract

0.1538mm from above. According to the above there are several

issues: One is that the standards are not identical. The other,

larger issue is that the ANSI standard allows plus or minus 0.007�,

(plus or minus 0.18mm), while the ISO standard only allows plus or

minus 0.05mm. Evidently, ANSI tolerates a variation which is 3.5 X

as great as allowed for ISO holders. Now for the relationship

between GG, film, and holder: You buy a holder, and assuming it is

of good quality, it will be within a narrow, acceptable standard,

preferably ISO. You load film in the holder. The first problem

arises in that you will either have transparency, thicker film, which

will be closer to the lens, or negative film, which will be further

away to the lens. For simplicity let us assume we standardize on

transparency film. Now, because the holder confirms to a narrow

variation in standard depth to the lens, so will the film. (Assuming

that film tolerances are narrower than holder depth). The next

question is whether the camera�s GG is calibrated to coincide with

the lens to film depth in the holder loaded with transparency film.

This is not a problem if your ground glass�s depth can be adjusted.

If it can and you have it properly calibrated, then you will have a

perfect match, but a match to only one type of film. If you decide

to change to negative film, then you will either have to readjust or

require a second back calibrated for negative film.

 

<p>

 

I have a Linhof Master Technika, which, very cleverly, allows very

precise adjustment of the GG depth. I calibrated my Linhof�s GG for

transparency film which I use exclusively and then left behind all

this stuff and just take pictures. To establish a perfect match

between lens to GG depth and lens to film depth all you have to do is

to measure both and adjust one, i.e. the GG, since you can�t adjust

the holder. It does not really matter at all if your holders are ISO

or ANSI holders provided their variations are small enough to be

acceptable to you. More importantly, your camera GG should be

adjustable. If the camera does not provide GG adjustment there is a

problem.

There is a technique that I have learned for testing holders thanks

to this forum. It is time consuming and tricky but not difficult.

I cannot afford Linhof or Sinar holders but have found Toyo holders

to be acceptable and much better than Lisco.

Some would argue that all this stuff is irrelevant. To me, the fact

that reputable manufacturers such as Sinar and Linhof take the

trouble to manufacture their holders to very tight tolerances and

that my pictures taken with a properly calibrated GG are now (not

before) extremely sharp is more meaningful than nay Sayers�

arguments. After all, with all the fretting that goes on about

which lens costing one or more thousand dollars is sharpest, more

people should instead worry if their $30 holder is good enough to do

justice to thousands of dollars invested in lenses, and of course,

that their GG�s be properly calibrated.

OK?

 

[sal_santamaura]

Thanks for the compliment, Julio. Your extensive research and

subsequent optimization of your *system* is very appropriate, and the

emitome of thoroughness.

 

<p>

 

I believe the reason for your success in making "extremely sharp"

pictures is that you've eliminated enough variables to keep the

emulsion within depth of focus limits. However, you still do not have

a "perfect match" between focal plane and emulsion. If you undertook

demanding work, as described at the end of my last post, you could

greatly benefit from the Schneider system. You'd be surprised how

much your film is rippling and buckling, even though you've calibrated

everything to get septums 0.009" behind your GG ground surface.

 

<p>

 

Your pointing out that transparency films are thicker is appreciated.

I don't use them (or color negative films) in large format, only

black and white, which is on a 0.007" thick base. My "solution" to

this whole problem, which also overcomes a current lack of space that

keeps the 4x5 enlarger stored in boxes, is to shoot 8x10 and contact

print. At 1x "magnification," even the Lisco holders - - which I've

depth checked at the store and limited purchase to those that fall

within the ANSI standard for 8x10 (+/- 0.016") - - provide critical

sharpness in my landscape work.

[julio_fernandez]

Sal: you are absolutely right about buckling and film warp. The

Schneider vaccum holder does eliminate that. Also, Sinar has a

holder with adhesive backing, seem to recall it is only available for

8X10. In 35mm and MF, Contax has vaccum systems as I am sure you

know. Good luck y'all.

[sal_santamaura]

The Sinar adhesive holder is (was?) available in 5x7 and 8x10.

According to a Sinar technical service rep I spoke with some years

back, those holders are made for Sinar by an outside vendor; Sinar

adds the adhesive strips. He said they are no more precise than Lisco

holders in terms of septum placement or film channel depth.

[bob_salomon3]

" To me, the fact that reputable manufacturers such as Sinar and

Linhof take the trouble to manufacture their holders to very tight

tolerances and that my pictures taken with a properly calibrated

GG are now (not before) extremely sharp is more meaningful

than nay Sayers� arguments."

 

<p>

 

All Linhof holders have been discontinued for a few years. That

includes the plate holders with the pressure plate and eject lever

and the double sheet film holders.

[sal_santamaura]

Welcome back, Bob.

[julio_fernandez]

Lisco holders: tests conducted on new and almost new Liscos (20) gave

me a plus or minus 0.007" variation in depth with the exception of

one of the holders which exceeded that variation. Toyo holders (4) on

the other hand gave a variation of plus or minus 0.002". The

statement from Linhof does not seem correct. Sinar specs are

published. Interesting to know that neither Linhof nor Sinar

continued manufacturing. That leaves Toyo as the best quality

choice. Please tell no one, the price may go up.....(!)

[david_kirk1]

Just a note to all those who responded, thanks for the input and help.

By the way I've just bought another one, giving me a numbered set

from 1 to 12, and this time Lee had managed to dig out a leafet which

came with it , and according to the blurb it is a douple cut

film/plate holder, designed to fit under the spring back of Super

Technika cameras. a very nice holder for only a tenner since I'm a

student. By the way there are still some avaliable so visit

www.quiggs.co.uk to see what's there.