Improving Sharpness

[bruce watson]

I'm looking to improve the sharpness of my negatives. If this means

changing the way I currently do things, so be it.

 

I'm using what are generally considered to be very sharp lenses. These

are the 110mm SS-XL, 150mm Sironar-S, and 240mm Fujinon-A. They all

look frighteningly sharp on the GG.

 

Currently I'm using Tri-X, HC110B, a Jobo CPP-2 processor (continuous

agitation). After testing, I find my personal EI is 400. I'm

developing for 5.0 minutes at 68 degrees. I don't want to go less than

5 minutes for fear of uneven development. Oh yes, I use a five minute

pre-soak - the theory is that this will tone down the excessive

contrast that results from continuous agitation. This gets me

negatives with good shadow detail, good tonality, but a bit dense

perhaps (Zone VIII shows a density of around 1.8).

 

The finished negatives are scanned on a drum scanner. That is, I'm not

printing to conventional silver papers. The "extra" density is not a

problem for a scanner.

 

Now, it may be that my expectations are just too high. What I want, is

to see the individual needles on a pine tree in the distance (that I

can see by eye standing next to the camera), nice and sharp in a 10X

enlargement. What I usually get is more fuzzy than I'd like, from all

three lenses.

 

First: is that a reasonable expectation for any film/developer

combination?

 

Second: If that's a reasonable expectation, how can I get there from

here? I'd like to keep using the Jobo, but I suspect that the Jobo and

HC110B are not a match made in photography heaven. I also want to keep

using a high speed film (I really like that extra couple of stops) such as

Tri-X or HP5+

 

So... please put me on the path to greater sharpness.

[dan_smith]

Make silver photographic prints. If you want sharp results, use the silver based film & silver photo paper & throw the damn scanner in the ocean. Why go to all the trouble looking for sharpness & then screw it up with another process entirely, one that softens what the negative has on it?

 

So, before you go postal & get pissed at the suggestion, try making a few enlargements on real photo paper using real photo chemistry & see just how sharp the results are (using an excellent lens & reasonable technique... or use a solid custom pro lab to make a few exhibition/reproduction quality prints) in comparison to the digi-prints you are now working on.

[tim_atherton2]

Ignoring Dans luddite ideology for now, you seem to have missed a stage (unless you just assumed it) - once you've gone digital, even from a drum scan, you need to know how to sharpen you image with more than just photoshops "unsharp mask" tool - it's a whole area of skills in itself, using various sharpening tools available, depends on what stage you sharpen at, and how you are printing.

 

BTW Dan - I can get lightjet prints from drum scans that are sharper than darkroom prints the same size (even though "sharpness" isn't something I obsess about in my images)

[dave schlick]

start with checking the camera and work down stream. buy a roll of velvia and shoot posotives and chech your lenses, tripod , rail sturdyness, depth of field release and etc etc.. once the camera is not suspect you can go on forward checking your negatives, then prints.. good luck.. dave.

[todd_caudle]

Dave Schlick's idea about buying a few sheets of Velvia are a good one, but there's a more obvious way. Lupe your negs. Are you seeing the pine needles on distant trees present on the negative? One can reasonably discern the correlation between what you see on a neg and what your final prints show.

[upscan]

Hogarth: You miss the cardinal point in obtaining the sharpest results. You are not alone as evidenced in several of the responses. This is no longer the 35 mm world where you can take registration as a given. This now is Large Format and registration is NOT a given. Registration errors measured in thousands of an inch can degrade sharpness.

 

You can not judge the sharpenss of a lens by how sharp it looks on the groundglass. Take one of your negs and view it at at least 10X magnification and decide if they are sharp. One teaching Pro, Joe Englander starts his workshops with checking registration and surprise, some of the student's cameras often have registration errors. You could have the world's best lenses but all will come to naught if registration is off. The groundglass or the film holders can throw registration off. Lens manufacturers (Zeiss, Schneider) know this is most important as people often blame their lenses and never think of checking the registration of their camera. It is as important as checking the air pressure in your tires. Doing it is more time consuming but as with your car, worth it.

[glenn_kroeger]

Sounds to me like either:

 

1. Your groundglass is misaligned. You need to check this optically by testing. There are several threads which include a variety of methods including a nice one published in View Camera Magazine by Robert Zeichner who posts here often.

 

2. You are misfocusing by a tiny amount. Make sure your loupe is focused in the image side of the groundglass.

 

3. You are using too small an aperture and getting diffraction softening. When I test lenses with transparency film (Velvia) I can JUST begin to see diffraction effects between f/16 and f/22 with a 30x lab microscope. But that effect is much too subtle to cause the sharpness loss you are describing. But if you are regularly using f/45 or f/64, the diffraction would be noticible.

[allen_whittier]

See if the negative looks as good as the ground glass. It's the first thing I do with a camera.

 

I have 15x and 25X loops. They tell me everything I need to know about my camera and lenses. Nothing gets past the 25x.

 

Hogarth, take a test photo with a wide open f stop. If your camera isn't focusing right your focus will be in front of or behind your actual focus.

 

I check my ground glass and holders with a machinest depth gauge. Most are within .020 inches of being the same. You need to remove the ground glass assembaly to measure the depth to the ground glass from the back. Be sure you measure to the ground glass in sandwiched glass assy's. .020" is fine for my work. Short, wide lenses get my best holders though.

 

Another thing to remember is the calculation for maximum acceptable circle of confusion. It's typically 1/1500th the distance from corner to corner of the film. It doesn't matter whether you're using a 35mm or a 11x14, at f11 the focus will be exectly the same at the extreme near and far focal distances. The distances will also be the same for both formats.

 

At prime focus the detail will go over the top with LF, but the rest is only slightly better than your 35mm. What you do gain is a lot of film available for tone changes. You also have all the movement in your lens to get most of your image into "Prime focus".

 

Are you using your camera to it's max to get those pine needles? Are they at prime focus with the ground glass and film at the same distance from the lens?

[scott_walton2]

One thing that has been missed over this thread. I do agree in the fact of

shooting a chrome to see if something is a bit off... this aside, you will be

happier with a higher acutance developer which will sharpen the edge of the

grain and have things more snappier as far as sharpness goes. I use Diafine

with TXP, Divided D76 (not as sharp but finer grain that HC110, D76) and my

prints pop with sharpness. I, like you, like a little denser neg because I print

with cold light and this allows me to print without filters most of the time and I

rate my 4x5 TXP @ 400 with great contrast and sharpness. There are a few

developers that are higher acutance and the ones that have potassium iodide

in the recipe will be the sharpest! I do have recipes if your up to mixing your

own...

[brian_ellis3]

This probably has no relevance to your problem but FWIW the five minute presoak is almost certainly a waste of time. I've never heard that presoaking has any effect on contrast but I'd be interested in learning more about it if it does. Where did you hear that? The usual reason given for presoaking is to minimize uneven development, primarily when trays are being used. Uneven development shouldn't be a problem with a Jobo system. So unless it does in fact affect contrast there's no reason to use it that I know of.

 

With respect to your problem, as others have said the place to start is with a loupe, a light box, and a negative. If the negative looks sharp then the problem is somewhere else along the line. If the negative doesn't look sharp enough for you then think about the tripod you're using, your focusing method, depth of field, alignment of the ground glass to the film plane, your film holders, and probably many other things that don't come immediately to mind. However, you sound like you're pretty meticulous so I doubt that it's a problem at the photograph taking stage, I'd place my bet on the scanning (maybe the equipment, maybe the operator) or the printer.

[ken_lee11]

I have the same Rodenstock and Fujinon lenses, and I scan my negatives. I have no problem with the pine needles: I even get the dew drops that hang beneath them. I use TMax, but I doubt it matters.

 

<p>Click <i><a href="http://www.kenleegallery.com/tech.html"> here</a> </i>to see some photos that demonstrate the sharpness of these two lenses. (You'll have to scroll down a little to the section on lenses. Click on the links.)

 

<p>If you would like to see a demo with pine needles, I'd be delighted to make one up.

[leonard_evens]

A couple of comments.

 

First, my theoretical calculations, confirmed by observation, show that I can't see individual pine needles at a distance greater than about 10 meters. I doubt if you can do a lot better than that without aids. I can easily make out separate pine needles at that distance on negatives at considerably less than 10 X magnification, at least in the principle plane of focus. If you can't see that kind of detail in the plane of focus under 10 X magnification, there is something wrong with your focusing, possibly a serious misalignment between the gg and the film plane.

 

Whether you can make out that kind of detail at the limits of the depth of field depends on how you set your acceptable circle of confusion. The value you choose determines the degree of magnification you expect to view the final image under. The standard least stringent assumption (0.1mm for 4 x 5) assumes about a 2 X enlargment to be viewed at about 10 inches. If you want to enlarge 10 X and also view at 10 inches, you would need to choose 0.02 mm, but of course that would give you much less depth of field.

 

Another point. At 10 X magnification, you may still be able to see very fine detail, but it is unlikely to appear very sharp. At moderate contrast the films we use provide not much more than 60 lp/mm. Even a perfect lens at f/22 will provide only about 70 lp/mm. Combining these by the more optimistic of the two rules generally used for that purpose yields about 45 lp/mm. If you magnify that 10 times you get 4.5 lp/mm which is just about what the human eye can resolve at about 10 inches. And that assumes everything else works just perfectly. So it seems to me doubtful that any grain snifter who puts his nose right up against a 40 x 50 inch print made from a 4 x 5 negative is going to see perfectly sharp detail at the limits of what the film and lens can deliver. Anything which appears sharp when viewed at 10 X magnification should be clearly visible at lower magnification, so he might as well stand back and enjoy the print.

[philip_glass]

Does anyone know of a website that explains how you check registration and correct for it?

[scott_killian1]

I also had some trouble with unsharp images from time to time and after trying everything I could think of, the culprit turned out to be very surprising: my tripod. I was using a Gitzo carbon fiber and Arca Swiss B1 head. Despite being rated by the manufacturer for cameras weighing more than my Ebony, it was simply underpowered and either had vibration or slight shake that would show up during longer exposures no matter how steady I was with the cable release. I switched to a Ries - in addition to getting a serious weight training workout and lots of hassle at the airport, I've also eliminated persistant sharpness issues.

 

Sounds too simple, but it worked for me.

[henry_a]

This may sound too obvious but are the pine needles you want to appear sharp in your photo the object on which you have focused? If not, it could be that they are far enough away from the actual plane of focus that they are unsharp. No developer or film change will help you with this. There is only one single plane of greatest sharpness surrounded by an area that gradually falls out of focus on both sides. For finest details it would be easy to think they might be acceptably in focus when you have focused the camera on a rock near them, but near is not exactly on them. The only part of the photo that will be absolutly sharp is at the plane of focus.

 

As for the digital part of this equation you can improve signfiicantly on the apparent sharpness of an image using sharpening and unsharp masking in Photoshop. That part is well proven, regardless of what others say. But I don't think thats your problem.

 

You can inspect your scans to prove any doubts about sharpness at a given point in your image. If you carefully focused on an object, inspect that object in the scan and then look both behind and in front of that object. Is the file sharper somewhere besides where you thought it would be? If so you may have a registration problem as previously suggested.

 

Finally, I don't know what your expectations are from 400 speed film but slower films will resolve finer details. A 10X enlargement puts you back in the category of a 35mm worker using say TriX versus TMax 100 and printing at 11X14 or so. No one would expect an 11X14 from a 35mm TriX negative to be as sharp and grain free or capable of resolving fine detail as one from a TMax 100 negative.

[bruce watson]

Ya'll have given me something to think about, and I thank you for taking the time to reply to my request. I do think I am now on the path to greater sharpness.

 

I didn't make it clear before, but it's the negatives - some of my negatives are not as sharp as I want. I only mentioned scanning because the negatives are somewhat dense for traditional printing, which is actually fine for a scanner. I have seen in the past that running the density up can cause sharpness to go down. At least, that's what I remember, but it's been a few years.

 

I ruled out the camera and lenses because I often do get excellently sharp negatives. I think that the camera is fine, but I'm going to check it again anyway just to be sure.

 

I think Scott may have hit upon my problem. I've been taking my tripod for granted (Gitzo 1227 with Arca Swiss B-1). Even though it holds a lightweight Toho doesn't mean that it won't move, especially if it's not on a firm foundation. The images that have been giving me problems do have something in common - all the ones I can think of are taken in the woods. Where I live, that means the ground is spongy with fallen leaves and pine needles, especially this time of year. It is hardly a firm foundation, so I need to pay more attention to making my setup as steady as I can make it.

 

Also, Leonard brings up good points. Perhaps I'm just being unrealistic with some of these images - can't get everything to be razor sharp unless you can get it to be planar for you! It does happen, but not often enough, unfortunately.

 

Thanks to all who have replied so far; thanks for making me think.

[ellis_vener_photography]

A 1227 is simply too light and doesn't have a wide enough foot print for a 4x5 camera. <P>Your camera might be a little vibration prone as well, especially if you are using exposures in the 1/60th to 1 sec range.<P> If you are just having a problem with some of your negatives it may be some particular holders. are not quite in agreement with your groundglass position.<P>And it may be that the pine needles are rustling a bit as well.

[gary_meader]

Hogarth- One more idea. You mention the high density of your

highlights due to the rotary processing. Could the fine, sharp

needles be encroached upon by the very light sky, where the

development is quite active? Sometimes this happens, and as

a test, I agree that you should shoot some chrome film and

check it out. Although the comment about focussing your loupe

on the INSIDE of the GG is a very good one, one that I'll certainly

check out for myself.

[scott_killian1]

It's ironic, the Gitzo 1227 was the same tripod I mentioned in my earlier post that gave me so many problems. Great for backpacking, but it really didn't provide a steady enough platform - especially when fully extended or when using longer lenses. My 300mm was almost never sharp when using this tripod.

 

Seems crazy to switch from a high-tech carbon fiber tripod to a classic wooden one, but it made all the difference in the world for me. Still use my B1 head without any problems - I found the Ries heads took too long to set-up and love the B1 design.

 

Good luck.

[bob_moulton7]

I agreee with those who suggest the problem may be in the making of the image. Focus, groundglass misalignment, bac misalignment, springs too weak to hold film holder--all are possibilities.

First, inspect your negs under a good lupe to see if they are as sharp as you want. If not, back to the camera. Developer/time/ devloping process would probably not account for what you are finding. Tripod rigidity could, as could the explanations given by others. IMHO, the scanner and the computer are less likely culprits. Again, look at the negs you have made. If they seem sharp then the scans are off most probably. Shooting Velvia and having it processed is a good idea. You could also shoot some Polaroid and with a loupe get an idea of sharpness also. But polaroid film and holders introduce a variable you would best avoid.

 

Good luck,

 

Bob

[jerald_brodkey]

I wonder if people who are having problems with tripod vibration

are using a cable release???

 

Jerry

[michael_alpert1]

After all the fine suggestions already offered, I hesitate to offer another; but here goes. It seems to me that pine needles are not a good subject to ascertain sharpness. You need to take a picture of something that doesn't MOVE. Also, pick something that is not prone to problems involving extraneous light. I also think a thorough look at the negative rather than a print (silver or digital) would be best.

[ken_lee11]

Here are some pine needles, with aforementioned dew drops.

 

First is the full frame image<div></div>

[ken_lee11]

... Now here are the needles:<div></div>

[bruce watson]

Ken,

 

That's what I'm talking about. Good get by the way. Very nice.