Help me figure out some problems with my 4x5

[rs1]

Hello,

<p>I recently acquired a Anniversary Speed Graphic with a 163mm f6.3 Ernemann

Special lens, plus a few film holders. I went out, exposed a few sheets ,and I

am consistently having the following problems.<br>

Apart from the obvious newbie errors of not leveling the camera, dust, etc., I

can't figure out what the band is on the left side of the image. It is a narrow

light coloured line running from top to bottom and it appears on all but one of

the negatives. Does this have something to do with the way the film is loaded?

Also the light leak on the top right is probably from the flap on the film

holder. I am guessing that some black tape will fix that one? But the band has

me stumped. <br><br>

 

Also, I did extensive web searches but couldn't find anything about this

Ernemann Special lens. In the image below, I used a fair amount of front rise

(no tilts possible with this camera) but it appears soft on top. Is the lens

reaching the limits of image quality already and without vignetting?<br><br>

 

Your help/advice/suggestions/reprimand is much appreciated.</p>

<br><img src="http://members.shaw.ca/rajivsankranti/lf.jpg">

[bob_stevenson]

The line down the lefthand side of the print is caused by light reflected from an 'edge' of something inside the camera/darkslide,....possibly the edge of the lip holding the film,...some matt black paint will do the job.

 

Concerning the light leak from the top/flap of the dkslide,....many of the older dkslides have provision for some disassembly in order to replace the light trap material,.....there may be tiny screws etc.,..'flocking' is readily available for renewal.

[jeff bishop]

This doesn't look like something that the camera is doing. It looks more like the sheet isn't completely submerged in the developer to me.

 

The obvious light leak is probably from where the darkslide goes in. As a habit, when I'm shooting the 4x5, I pull the darkslide out, but not all the way out. That seems to take care of this for me.

 

Hope this helps!

[pico_digoliardi]

I am not familiar with your particular film holders, but none of mine can possibly leak about the flap. The tape merely keeps it in place and allows it to be opened for loading/unloading.

 

Now it appears that your film was not loaded under both retaining tab-rails. Look at the top and bottom. If your holder has both (and IMHO it should), your film is far from flat in the holder. It's a common beginners error, so don't feel bad.

 

I agree with the chap who suggests that the top right is likely a processing error. That part of the film should be well covered by the flap (which should be lightproof regardless of the tape.)

[james_meckley1]

I second Bob's opinion that the band down the left side of the image is caused by light

reflecting from a narrow surface inside the camera, almost perpendicular to and just in front

of the film. I've had to design baffles for a couple of my cameras to combat just such a

problem.

 

If it were an area getting insufficient development, it would be darker, not lighter, than the

rest of the image.

[leonard_evens]

I agree that the band is probably some reflection from something inside the camera. It is possible that you may be able to see it by removing the lens and shining light around the interior in a dark room.

 

I don't know anything about your lens, but if what you posted is representative, it doesn't seem really sharp anywhere. That could be the fault of the lens or failure to focus properly. Another possible factor might be field curvature. That might show itself because different parts of the field come to focus at different positions of the lens. Usually you can get around that by focusing at an intermediate position and stopping down.

[rs1]

Thanks for the answers. I'll check the camera and holder and see if there is any reflective surface that is causing this.<br>

The camera was set at f22 and focused at a hyperfocal distance of 30ft.<br>

The image is a contact print and was scanned in with no additional sharpening. Examining the negative with a 8x loupe, shows that the far building is sharp (you can see inside the windows) but the close building is soft at the top but sharp at the bottom.

[j.w.]

Rajiv, I've had the same problem on my Anniversary Speed Graphic; the problem turned out to be the film holder. It seems that some of my holders had wear on the black finish along the inside aperture surfaces, adjacent to the darkslide, to the degree that the surface becomes reflective to light. I have a beautiful contact print of a roadway exiting a tunnel; the shot would be perfect except for the reflection off the inside edge of the holder.

 

The tell-tale clue is the thickness of the band of fog.

 

Given the light leak also around the felt trap or door area, you may want to consider just getting a new holder. You could try repainting the culprit reflective surface, but you may have problems with paint flaking off making spotting problems.

[pico_digoliardi]

<b>James</b> <i> If it were an area getting insufficient development, it would be darker, not lighter, than the rest of the image.</i><p>

 

Yep. I just hate it when I mess up like that. :( Listen to James.<p>

Humbly,

Pico

[leonard_evens]

Note that if you examine the negative under 8 X magnification, you are effectively increasing the hyperfocal distance by a factor of 8. That is because the hyperfocal distance depends on a criterion you use for sharpness, called the circle of confusion, and under higher magnification you need a smaller coc for the image to appear sharp. So the hyperfocal distance would become something like 240 feet. If you focused at 30 feet, the DOF would range from 27 feet to 34 feet with that hyperfocal distance. But that is enitrely inconsistent with what you say. It seems likely that you were actually focused at a significant distance perhaps even at infinity. The fact that the top of the closer building is not sharp while the bottom is would then make sense. Theoretically, the DOF region is bounded by two planes perpendicular to the lens axis; it forms an infinite vertical 'slab'. But for a real lens, particularly an older lens of unknown quality, field curvature and other faults will restrict the DOF region in such a way that it extends more along the lens axis than away from the axis. That would make sense of what you see.

 

Your focus could be off for several reasons. First, there is always a certain focusing error whatever method you use. Second, the film plane may be displaced relative to the ground glass. You can test some of this as follows. Tape a sheet of newsprint on a wall with the print running vertically. Make sure you check that the wall is plumb and so are the lines of print. Place your camera at some distance, say about 5 -10 feet from the wall, level it carefully, and point at a line of print using a loupe. Take one or more pictures. Then examine the negatives carefully with a loupe to see how far off the center of focus is from the line you focused on. Measure it as best you can, and convert to mm. (Multiply inches by 25.4.) You can estimate how far off you are in the position of the film plane as follows. Calculate the distance from the lens to the target in mm. Divide that by the focal length, subtract 1, and square the result. Divide the measured focus shift in the subject by the number you just got, and that will give you a good estimate of the shift in focus on the film side of the lens. I think anything larger than about half a mm would be too much. Many people would think it should be even less than that. My guess is that you will find that you are much further off than that, perhaps as much as 2-3 mm.

[rs1]

Leonard,<br>

Thank you very much.<br>

<p>I am going to do what you suggested. I would hate for the film plane to be off because the camera will be pretty much a piece of junk (unless I can fix it). On my other photos where I didn't use any movements, I did get a uniformly sharp negative. So hopefully it's the curvature of field issue with this lens rather than the camera. <br><br>

I used the hyperfocal spreadsheet calculator from Harold Merklinger's website. I set a max coc of 0.08mm and generated that hyperfocal distance table. But it is very likely that I didn't actually focus at the hyperfocal. I think I most probably focused on the first building which was at least 100 ft away.<br>

Thanks again for your excellent suggestions and advice.

[kelly_flanigan1]

Ernemann Special; wow. Ernermann is an ancient brand, but today there is the Ernemann Special film projector for Laser Audio.

[leonard_evens]

Rajiv,

 

Is it possible that you miscalculated? The usual formula for the hyperfocal distance is the square of the focal length divided by the product of the coc and the f-number. Using 0.08 mm for the coc, 163 mm for the focal length, and 22 for the f-number, I get about 50 feet for the hyperfocal distance. (You sometimes see another possible formula for the hyperfocal distance, but it shouldn't give a significantly different result.)

 

I looked for the calculator you referred to at Merklinger's website, but I couldn't find it.

 

For distant objects the near and far depth of field boundaries are obtained by dividing the product of the hyperfocal distance and the focusing distance by the hyperfocal distance plus the distance in one case and by the hyperfocal distance minus the distance in the other case. (If the difference is zero or negative, the far limit is at infinity.) Using 240 feet and 100 feet, that gives 24000/340 = 71 feet and 24000/140 =171 feet. If the near building was a little over 71 feet and the DOF near field curved away from the lens, which is quite possible for what you described, then you would see just what you described.

 

In passing, let me note that there is a very interesting article in the latest View Camera by Robert Hallock which explains the limits of visual acuity. Roughly, when viewing an 8 x 10 print at 12 inches, a typical viewer can see somewhere between 5 and 10 lp/mm (and some can see even better). This corresponds to a coc of anywhere from 0.2 to 0.1 mm for viewing at that distance. Since a 4 x 5 negative is enlarged by a factor of two to get an 8 x 10 print, you divide by two to get the coc at the level of the film. That would give from 0.1 mm to .05 mm and your 0.08 is well within that range. But keep in mind that if you look at a contact print from a 4 x 5 negative at normal close viewing distance (10-12 inches) you won't need that small a coc. In your case 1.6 mm would suffice. If you could manage to get 5-6 inches away, the lower value would be appropriate. For general purposes, however, the 0.08 mm is best since it not only tells you about 2 x enalrgements but also about greater enlargements under the assumption that people get proportionately further away when viewing larger prints.

[rs1]

Leonard,<br>

You are absolutely right! I don't know what I was smoking when I said 30ft. I need to revise my cheat sheet because the numbers on it are wrong. I checked the spreadsheet and it does say 49.3 ft for coc of 0.08. I think I mixed up the values for another focal length because I also have a 150mm Schneider Xenar. <br><br>

The spreadsheet is on this website:<br>

<a href="http://www.trenholm.org/hmmerk/HMbook18.html#anchor1110801">http://www.trenholm.org/hmmerk/HMbook18.html#anchor1110801</a>

[User_503771]

Regarding focus, it could very well be that your lens is not made to use many movements on a 4x5. Quite a few of the 135mm lenses back then were made to cover 9x12, not 4x5.

 

You might get sharper photos with the front rise if you stop it down more. But watch out and check your focus after stopping down, in case the focus shifted (not real likely, but possible).

 

As above, it could also be that something is out of register. Maybe the ground glass panel needs some shims to put the glass into the same position as the film plane.

 

Or, maybe the front standard had a little bit of tilt that you weren't aware of when you shot?

 

I can't find any data about a "Special". Do you have a more complete name for this lens? Ernemann made a lot of lenses for many cameras....

[kelly_flanigan1]

A 163mm lens should cover a 4x5" film size if it is a triplet or tessar type design. <BR><BR>The old pre WW2 Kodak K.A. #32 is a "tessar" type design that covers a 4x5" frame and is a 6 3/8 inch F4.5 lens, ie 162mm.<BR><BR> The longer Kodak K.A. #33 covers a 5x7 frame, and is a 7 1/2 inch F4.5 lens; ie 191mm. <BR><BR>A rough rule of thumb is a Tessar type lens will cover roughly its focal length in film diagonal

[rs1]

The lens says "165mm F/6.3 Ernemann Special.....Made in USA". That's it.

My apologies for saying 163 before. It's 165. <br>I think it is a tessar (it has two strong and one weak reflection when viewed from the back) and it also seems to be coated. So probably late forties early fifties?

[allen_whittier]

I tend to agree with Bob. It�s s reflection off the lip or the film holder.