Disappointing results with my Crown Graphic

[Sirius Glass]

So does Steve Choi at Steve's Camera Repair in Culver City CA

I think so, but I am not sure. Give him a call.

That wasn't a question.

Oh, I am so embarrassed!

 

[tim48v]

More data. Here are three more scans, two with the camera "as is"; one with the film holder shimmed out 0.2mm.

It looks to me like I need to shift the gg/Fresnel about 0.1mm forward.

 

[RobC]

I'd say probably 0.15mm from what I can see. But as you now know, getting your focus spot on isn't so straight forward even though I'm sure you were being careful. Its very easy to make a mistake with focussing.

If you did a ruler test with F11 or smaller I don't think you would notice the GG position error. And for your landscape images at distance I don't think its going to make a visible difference. Its more likely your focussing was off or the lens is not great for some reason or camera vibration.

 

[Ian Grant]

I'd also check the film holders, it's just possible they aren't standard it's not unknown.

You can't shim the screen forward and machining the frame is not a good idea as it's correct as it is. It's far more than just grinding down some bosses every edge the fresnel sits on would need grinding as well.

It would be far better to try a different focus panel on the camera and check out what's really wrong, like Shutterfinger (45PSS on graflex.org) I also repair and restore cameras including Spped & Crown Graphics and that's the first thing I'd do. I'd also compare the fresnel with a genuine Graflex Ektalite and see what difference that makes and fit a new GG screen which should be significantly brighter than an original Graflex GG.

Ian

 

[tim48v]

Everyone,
It seems that the first thing to do is replace the ground glass. It is cracked anyway and could easily be off by 0.006". I hadn't realized that I was looking for such a small error or I would have replaced it before the test shots.

However, as others have mentioned, that doesn't explain everything. I think camera shake is also a major factor (maybe the main factor). Now I need to find a bigger, sturdier tripod. For nostalgic reasons, I'd like a wooden one but am worried about weight and cost. Any suggestions?

Thanks for all the advice. I'll update this when I have the issue resolved.

 

[Sirius Glass]

I found that the Induro tripods are a very cost effective light [carbon fiber] tripod. They have a $50 off special right now. You will also have to buy a tripod head. http://www.indurogear.com/products/tripods/

 

[Neal]

Dear tim-48v,

I really don't think there is a problem with the gg position. There is always a bit more DOF behind the focus plane than there is in front of it. Shimmed out it looks the other way around. In any case, the difference between the two positions would not explain the original photos.

In any case, the new photos appear much sharper than the ones in the first post.

Neal Wydra

 

[Sirius Glass]

Dear tim-48v,

I really don't think there is a problem with the gg position. There is always a bit more DOF behind the focus plane than there is in front of it. Shimmed out it looks the other way around. In any case, the difference between the two positions would not explain the original photos.

In any case, the new photos appear much sharper than the ones in the first post.

Neal Wydra

Good point: There is always a bit more DOF behind the focus plane than there is in front of it.

 

[Ian Grant]

Everyone,
It seems that the first thing to do is replace the ground glass. It is cracked anyway and could easily be off by 0.006". I hadn't realized that I was looking for such a small error or I would have replaced it before the test shots.

However, as others have mentioned, that doesn't explain everything. I think camera shake is also a major factor (maybe the main factor). Now I need to find a bigger, sturdier tripod. For nostalgic reasons, I'd like a wooden one but am worried about weight and cost. Any suggestions?

Thanks for all the advice. I'll update this when I have the issue resolved.

I don't know where you're located but strongly suggest before you do anything find some one local with a Pacemaker Graphic and check your back against theirs, a spring back is only held in place by 2 screws , if it's Graflok it's even easier.

Ian

 

[trondsi]

For what it's worth, I'm having a somewhat similar problem, but with my CG optar lens. It's not terrible, but I wonder if my Rolleiflexes have spoiled me a bit. It looks like the optar can't match the Rollei lenses even when at the highest f-stops. Either that, or I'm not that good at focusing.

 

[shutterfinger]

If you want a really good wooden tripod try https://www.berlebach.de/?sprache=english . I have a Report and it way overkill for a Crown Graphic but it is rock solid.
The tripod head is usually the major cause of vibration with the legs second.

Film surface depth of a film holder should be .197 inch ± .007 inch for 4x5 format. TriX sheet film is .007 thick.
http://home.earthlink.net/~eahoo/page8/filmhold.html

Always use a good 4x to 6x loupe when gg focusing. The quality of the gg will affect the ease of focusing.

 

[Jim Jones]

If you want a really good wooden tripod try https://www.berlebach.de/?sprache=english . I have a Report and it way overkill for a Crown Graphic but it is rock solid.
The tripod head is usually the major cause of vibration with the legs second.

Film surface depth of a film holder should be .197 inch ± .007 inch for 4x5 format. TriX sheet film is .007 thick.
http://home.earthlink.net/~eahoo/page8/filmhold.html

Always use a good 4x to 6x loupe when gg focusing. The quality of the gg will affect the ease of focusing.

Don't rely on the information in the above link. Someone may have had good intentions when they posted it, but a few errors crept in. The figure for the cited "Depth to film surface" is actually the so-called "T" distance to the septum, which may or may not coincide with the back surface of the film. The slot the film rides in is specified to be 0.012 inches, while film may be about 0.007 inches thick. Therefore, the film should be closer to the lens by several thousands of an inch. The "Exposure Height" figures are the minimum long dimension for the slot the film rides in. The Exposure width dimensions are also incorrect. I'm relying on a 1951 ASA spec sheet for information.

 

[shutterfinger]

I have always had excellent results using the specifications to check my holders for errors and ground glass positioning. I measure to the backing plate of the holder and let the tolerance range handle the film thickness.
For critical work put a sheet of your regular film in a known good holder, the holder in the camera back and measure from the back frame to several points on the sheet of film then adjust your ground glass to match the film.

 

[John Koehrer]

There's an OTTO tripod in the classifieds. Says it's made by Ries.

(there was a url link here which no longer exists)

 

[removed account4]

tiltalls are not expensive and last a long time.

 

[RobC]

Some figures that everyone might find interesting. They may of course send you to sleep but read on as they may just give you a clue about LF performance and could help you disuade you not to take that route, unless you're an eternal optimist.

With LF you are using a floppy sheet of film which can and will move forwards and backwards in the film holder slot and there's very little you can do about that. Sinar used to make film holders to remedy this by holding film under tension or using a tacky film holder back for 8x10.
How much can the film move in the slot? 0.5mm or possibly more. Bear that in mind when looking at following figures.
The figures are looking at depth of focus (not depth of field) i.e. at the film plane and not the focus plane in the subject.
Using two example distances of 2000mm and 12000mm and 4 example apertures of 5.6, 11, 16 and 22.
Target min CoC is what is considered acceptable. If everything is perfect you can approach the theoretical limit but that rarely happens in the real world.

All numbers in millimeters (except aperture). And note Depth of Focus is + or - value from film plane.

[TABLE="width: 600"]

Focal Length

150

150

150

150



Aperture

5.6

11

16

22



subject distance

2000

2000

2000

2000



CoC (theoretical min) in millimiters

0.009

0.0158

0.0231

0.0317



Depth of Focus for theoretical min CoC + or -

0.0545

0.189

0.4

0.754



CoC target min in millimeters

0.03

0.03

0.03

0.0317



Depth of Focus for target min CoC + or -

0.182

0.357

0.519

0.754


[/TABLE]

[TABLE="width: 600"]

Focal Length

150

150

150

150



Aperture

5.6

11

16

22



subject distance

12000

12000

12000

12000



CoC (theoretical min) in millimiters

0.0076

0.0149

0.0216

0.0296



Depth of Focus for theoretical min CoC + or -

0.0431

0.166

0.35

0.662



CoC target min in millimeters

0.03

0.03

0.03

0.03



Depth of Focus for target min CoC + or -

0.170

0.334

0.486

0.668


[/TABLE]


A modern 150 lens MTF will show you that it will perform quite well at F11. However, the floppyness and movement of a sheet of film by as much as 0.5mm means that you will be very very lucky to get that full perfomance of the lens. Only when you get down to f16 will lens performance largely cover film plane inaccuraccy and f22 to be sure. But this always happens at the cost of potential on film resolution. So its not so much that lens is optimised for f22, its that film holders just can't consistently give required performance.
i.e. the wider the aperture the more likely you will run into film positioning inaccurances with LF.

Best to adopt a policy of rapping film holder in a consistent way before inserting into back so that film tends to always be in same position in film holder.

This film position inaccuracy due to film holder design is probably the main reason why you don't see a very large jump in quality when you move from MF to LF. It is also one of the main reasons why I stopped doing LF. I got tired of thinking I was doing everything right only to find a high failure rate which was certainly not all down to me. You just can't control film inside the film holder and it WILL casue unexpected failures of sharpness which is extremely frustrating because you are never sure whether its you or the sheet of film position in the holder. And when you add in your own focussing errrors and standards not being parallel when they are meant to be etc etc then it seemed all too much for me. It took too long to get the consistency I wanted in the time available when do a long walk in the countryside.

Also note that figures relate only to a theoretical 150mm lens.

 

[winterclock]

How did you come up with 0.5mm? If the slot is 0.012" and the film is 0.007" the allowable movement is 0.005", that would be about 0.12mm wouldn't it?

 

[RobC]

there are various makes and models of filmholders. Do not assume they confirm to any standard becasue they don't. And film flexes.

0.5mm is an arbitrary number. Sometimes if you open a dark slide and touch the film it is firmly against the backing plate but other times it is "a distance" from the back plate which I consider to be upto 0.5mm. But whether its 0.5, 0.3, 0.1 or flat against the backing plate, illustrates that its not always in the same position and therefore it will often be out of position for optimal on film resolution. That's a fact. Some people don't worry about it, others do. I say close down to f16 or f22 and you should be OK (ish) most of the time.

 

[removed account4]

Some figures that everyone might find interesting. They may of course send you to sleep but read on as they may just give you a clue about LF performance and could help you disuade you not to take that route, unless you're an eternal optimist.

for me,
the moral of the story isn't to ... NOT use LF,
but to use it and not worry about that technical "stuff"

been using it since the 80s professinally and for personal enjoyment
and i have never once even cared about the circle of confusion,
and theoretical depth of fields were.
if one worries too much about the small stuff they won't ever take any photographs.

my advice to the OP ...
make sure your groundglass and film are seated correctly,
get a tripod ( it doesn't need to cost 200$ and have a 400$ multi axis head )
get a shutter release and don't worry about the small stuff.
expose your film between 16 and 22 and have a good time.
if you are still dissatisfied with the 2 lenses you have
( i have both a symmar and a few optars and they have never given me trouble for nearly 30 years,
but there have been duds, maybe people who thought they knew how to repair things " repaird them "
or they were manufactured on the mythical monday or friday )

rent or borrow another lens and see how that works.

LF shouldn't really be this difficult, its just a box, a tripod film and a lens...


good luck !

 

[RobC]

LF shouldn't really be this difficult, its just a box, a tripod film and a lens...

This is true but when you have just acquired an old camera and are having focus problems, then these things need to be checked. And you can't do it properly if you don't understand what is going on AND can interpret the measurements you are taking in a sensible way.

 

[Ian C]

I measured the distance from the face of the holder to the surface of the septum plate of a random sample of 13 empty 4” x 5” holders. This is the so-called “T” distance. I used a 6” Starrett dial caliper and Starrett 120D Depth Attachment to make the measurements.

The diagram and the table given in the following link are correctly labeled as “Depth to film surface”.

http://home.earthlink.net/~eahoo/page8/filmhold.html

The FILM SURFACE in this case is the base surface of film—the surface that rests upon the septum plate—not the emulsion surface. Obviously film thicknesses can vary slightly. This is a dimension standard for film holders—not for the film holder with a sheet of film in place.

The following are the holder brand or model, the face-to-septum plate dimension of the first side, and that of the second side:

Fidelity Rite-Way

0.204”, 0.204”

0.195”, 0.195”

0.199”, 0.197”

0.199”, 0.199”


Lisco Regal II

0.198”, 0.196”

0.194”, 0.192”

0.194”, 0.195”

0.196”, 0.194”

0.196”, 0.194”


Baco (Hollywood, CA, wooden)

0.200”, 0.205”


Toyo

0.194”, 0.194”


Crown

0.194”, 0.196”

0.195”, 0.196”


The average of these 26 measurments is 0.1967” and standard deviation is 0.0034”

I also measured the thickness of a 4” x 5” Kodak T-Max 100 negative as 0.0077” = 0.196mm.

 

[RobC]

back when I measured various film holders for depth I found that there was a significant depth distance between some new (at the time) toyo holders and fidelity (also new) holders.
I also found that using a micrometer depth gauge (very accurate fine measurement) that there was a difference between when it touched the film and when the the torque clcik happens as you turn it down. This is important becasue it would never click until it pushed the film against the backing plate (septum plate) so I had to watch the film to see when it moved to get accurate reading otherwise I would always get a reading of backing plate plus film thickness. The backing plate would also flex before the micromter clicked so great care needs to be taken about this.

Fact: film depth will vary according to how it is sitting in the holder. You just can't get a way from that.

If you have checked that focus is accurate and you use all the same make and model of film holder, then at least you should get fairly consistent results. But occasionally you get a bad one, probably a combination not precise focussing and film position.

 

[Jim Jones]

Ian, thank you for doing what most of us haven't bothered with. Your data must be intimidating to photographers who use an Aero Ektar wide open. The "T" distance in the 1950 ANSI data sheet is clearly shown to be the distance to the face of the septum, not to the film . Perhaps they have changed that in the intervening 65 years. I'll leave it to someone else to research newer published data.

 

[Nokton48]

I've had these 4x5 Linhofs and recently picked up some in 9x12cm.
I seem to recall that Marty Forscher was collimating something, and popped one of these in.
With the spring-loaded pressure plate, resolution went way up.
Anybody here try these?

001 by Nokton48, on Flickr

 

[removed account4]

This is true but when you have just acquired an old camera and are having focus problems, then these things need to be checked. And you can't do it properly if you don't understand what is going on AND can interpret the measurements you are taking in a sensible way.

i agree with you to a point but ... ...

circle of confusion charts
and information about depth of focus for min/max circle of confusion
down to the 1/1000mm or 1/10000mm is interesting .. but a bit excessive.

its like someone having trouble with their car and someone talking about
the minutia regarding throddle bodies or the precise measurement of carbureted mist sprayed into
the piston heads ... when the answer is much simpler (dirty spark plug)..

unfortunately, complex answers to simple problems
seems to be the way of the internet