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Keith Tapscott.
22-Apr-2008, 06:46
I have posted this question on another LF forum (UK), but will ask here as well to get some more advice.

I have finally had some of my 4x5 negatives enlarged onto 16x20 paper by a photographer who lives locally to me. He sent the prints back to me with a note saying that the negatives looked to be of good quality concerning exposure and processing but the image sharpness of the prints looks slightly soft overall.
The photographs were taken on 4x5 T-Max 100 using a 180mm Symmar-S on an MPP Mk VIII. I used a Toyo 3.6X focus-aid on the screen to ensure that the main part of the subject was in sharp focus, but even this is on the soft side on the enlargements. What am I doing wrong?

Dan Fromm
22-Apr-2008, 06:54
Which film holders (double darks in britspeak) were you using? I ask because IIRC MPPs' ground glasses are a little out of register with standard holders.

Keith Tapscott.
22-Apr-2008, 06:59
Which film holders (double darks in britspeak) were you using? I ask because IIRC MPPs' ground glasses are a little out of register with standard holders.
Hi Dan,

I used 100TMX in a Kodak Readyload holder if that helps.

Ralph Barker
22-Apr-2008, 07:00
It's difficult to say without examining the negatives, but the softness could be a result of any number of issues. This includes improper spacing of the mounted lens, a poor example of the particular lens (or damage that isn't obvious), a variation in the GG position relative to your holders, or camera vibration during exposure. Note that if there's a GG position problem, something other than what you focused on should be sharp. Standards not being fully locked down might also cause a shift in the plane of sharp focus.

Keith Tapscott.
22-Apr-2008, 07:13
It's difficult to say without examining the negatives, but the softness could be a result of any number of issues. This includes improper spacing of the mounted lens, a poor example of the particular lens (or damage that isn't obvious), a variation in the GG position relative to your holders, or camera vibration during exposure. Note that if there's a GG position problem, something other than what you focused on should be sharp. Standards not being fully locked down might also cause a shift in the plane of sharp focus.
The prints look like they are slightly out of focus and lack pin-sharp definition. I know this isn`t due the guy who enlarged them for me. The Camera was on a good tripod with very little breeze, so I don`t think Camera shake is the problem. The GG position might be the culprit, but I`m not know how to check for this.

Scott Kathe
22-Apr-2008, 08:28
I think I've seen a set up where you put a ruler on a table. Angle you camera down just a bit and focus on one number in the middle, numbers closer and farther will be out of focus. Shoot wide open and see what is in focus on the negative. If it matches up-great. If not you should be able to tell if your film is too close to the lens or too far away depending on where the focus point is.

Scott

Dan Fromm
22-Apr-2008, 08:41
Keith, according to info here http://www.mppusers.freeuk.com/ your Mk. VIII has the standard 4x5 register. Scott's advice, to find out where the actual plane of best focus is, is good.

Good luck, have fun,

Dan

Ralph Barker
22-Apr-2008, 09:02
If the "ruler test" indicates a problem with the GG placement (as might happen if the GG was replaced at some point), you can use a micrometer depth gage to determine how much to shim or trim the GG. Measure from the surface of the frame holding the glass, after removing the back, to the surface of a sheet of film, and then compare that to a similar measurement on standard holders.

Keith Tapscott.
22-Apr-2008, 11:48
Thanks to Dan, Scott and Ralph for the advice and suggestions. The guy who enlarged the 4x5 negatives for me uses a Technikardan and had a similar problem himself when he first used his Camera. He has offered to to take a look at the Camera for me and has some gauges and other tools for measuring alignment etc.
It wont be this week, but I will report back later and write what the problem was.

Thanks again,

Keith.

Leonard Evens
22-Apr-2008, 14:18
A difference between the gg position and the film plane can explain focusing problems. If that is the case, something should be in very good focus, just not where you though you had focused. Of course, if the in focus plane doesn't contain anything of interest, it may be hard to find, but it is at least worth a try looking.

Another possibility might be failure of the film to lie flat. Again there should be something exactly in focus, but it may not be in a plane or even a simple curved surface.

Finally, it may be that your standards aren't parallel. That would tilt or swing the plane of exact focus. Again, something should be in focus in the picture. He is how I check that. I use a level to make sure the gg is vertical when is the rail or bed is level, as it should be in the detent position. If it isn't, I adjust it . There is usually some play in the detent or zero position which will allow that. I then turn the camera so it is pointing downard and the gg becomes level in what was the vertical direction, and I check if it is level in the other direction. If not I adjust the swing. Using a torpedo level across the ends of lens barrel, I next check if the front standard is level in all directions and adjust its tilt and swing to make sure it is. When I'm done, I'm sure the standards are parallel.

If none of these suggestions help, and image is just fuzzy everywhere, there is something else going wrong. If you stop very far down, diffraction could cause a slight fuzziness in a large print. Otherwise, it must be something about the lens. Either it is defective or it was designed to be "soft focus" to begin with.

Jim Jones
22-Apr-2008, 19:29
Slight misfocus could be because of a fresnel has been installed or removed without an appropriate GG adjustment.

tim810
22-Apr-2008, 20:20
One problem I have come across on two occations is film shift inside the holder while exposing film. This will create an unsharp image across the entire piece of film. Now, I make sure that I gently tap my holder on a surface before I load it into the camera. I don't know the durration of the exposure but anything longer than 1/10 th or so will regester this shift.
Tim

Keith Tapscott.
23-Apr-2008, 01:32
The lens used was a 180mm Symmar-S and the original GG was replaced with a Satin-Snow. The lens appears to be in very good condition. Lots of advice and suggestions from this thread to try.

Many thanks.

Dan Fromm
23-Apr-2008, 02:49
Keith, when you put the new GG in did you place it with the ground side facing the lens?

Keith Tapscott.
23-Apr-2008, 04:26
Keith, when you put the new GG in did you place it with the ground side facing the lens?
Yes and I would have thought that Kodak Readyloads in a Readyload holder would keep the film quite flat.

Keith Tapscott.
26-Apr-2008, 13:53
This article , pointed out to me by an APUGer has been very informative. I will get back to you on this, as he has been very helpful.
http://www.largeformatphotography.info/holders.html

Bruce Watson
26-Apr-2008, 14:12
It's difficult to say without examining the negatives, but the softness could be a result of any number of issues. This includes improper spacing of the mounted lens, a poor example of the particular lens (or damage that isn't obvious), a variation in the GG position relative to your holders, or camera vibration during exposure. Note that if there's a GG position problem, something other than what you focused on should be sharp. Standards not being fully locked down might also cause a shift in the plane of sharp focus.

Since no one else is saying it, I guess I will. It could be user error. I had similar problems early on -- couldn't get anything to be razor sharp. It was always close, but off just a bit. This went away for me when I increased my total loupe power to about 6x (I'm using custom glasses (to correct my astigmatism) for about 2x, with a 4x jeweler's loupe for a total of about 6x).

I also have a readyload holder that's actually bowed on the front surface. Markedly. But the thing works beautifully for some reason. I found this huge stone wall and shot some 100Tmax with an 80mm lens wide open (very small depth of focus) and it was razor sharp edge to edge and corner to corner. But the fact that it's not really flat on the surface facing the lens still bugs me...

jetcode
26-Apr-2008, 14:25
I used a Toyo 3.6X focus-aid on the screen to ensure that the main part of the subject was in sharp focus, but even this is on the soft side on the enlargements. What am I doing wrong?

I've had nothing but problems using the Toyo 3.6X focusing aid. It is not the best optic to use for obtaining a sharp image on GG. Even when you think it's sharp there is a slight unsharpness (soft). When I stepped up to a higher quality Schneider loupe the game changed. I started getting sharper results. Use a quality loupe, avoid camera shake at all costs, including bumping the camera before making an exposure shifting the position slightly. It also helps to be able to see the image clearly as often low light levels on GG can make focusing very difficult.

This is the loupe I use. It provides a 2:3 linear window of observation and is noticeably sharper.

http://www.bhphotovideo.com/c/product/214580-REG/Schneider_08034560_6x_Aspheric_Magnifier.html

Bill_1856
26-Apr-2008, 19:35
Have you looked at the negatives with a magnifier? Just because the prints are fuzzy doesn't mean that the negatives weren't sharp.

Keith Tapscott.
27-Apr-2008, 01:54
To bruce and Jetcode, it may be down to some error on my part and I will take some more photos soon, although I am interested in the problem of using the Toyo loupe, is there a fault with that product, or maybe Jetcode has a bad one?

jetcode
27-Apr-2008, 04:38
To bruce and Jetcode, it may be down to some error on my part and I will take some more photos soon, although I am interested in the problem of using the Toyo loupe, is there a fault with that product, or maybe Jetcode has a bad one?

it's not a Toyo loupe, it's a Toyo focusing aid. It's not a high quality optic and I am glad to get it out of my kit. That slight extra sharpness you are looking I found by putting a better optic between my eye and the ground glass. Seriously as much as film costs I can't imagine using anything less.

Ralph Barker
27-Apr-2008, 05:49
Preferences in loupes vary. I've been using a Toyo 3.6x loupe for years, and have generally been happy with it - except when trying to examine the corners of the GG. Is it as good as my Schneider 6x6? No, but the Schneider was an order of magnitude more expensive, in addition to being larger and heavier.

Keith Tapscott.
27-Apr-2008, 06:01
A photographer who lives locally kindly measured the GG of my MPP for me which was 4.90mm. The Toyo DDS was 4.67, the Fidelity Elite was 4.80 and each of the DDS`s had a sheet of film in the holder. The Kodak Readyload holder with a sheet of film was 4.87 and the closest to the GG.

Error on my part when focusing might have been the problem as I couldn`t remember if I refocused after applying a bit of forward lens tilt or not, so I will have to take some more photographs soon when I have a bit of time to spare. :o :confused:
From left to right, the screen ran from 4.92 to 4.87, so a little bit of discrepancy there, although I`m not sure if it`s enough to make a major difference.
I must confess that the mention of the Toyo X3.6 has got me a bit flustered though.

Thanks everyone.

jetcode
27-Apr-2008, 06:55
Preferences in loupes vary. I've been using a Toyo 3.6x loupe for years, and have generally been happy with it - except when trying to examine the corners of the GG. Is it as good as my Schneider 6x6? No, but the Schneider was an order of magnitude more expensive, in addition to being larger and heavier.

A big factor is my ever failing eyesight and resolving detail which is why I chose to stick to Copal 3 glass rather than the Fuji lenses. I originally bought the Schneider to replace a loupe I lost for my light table. Then I found the rest of my loupes and gave them a side by side and the Schneider had the edge. The Schneider I have is larger in circumference but isn't all that different in weight IMO, in fact I think it is lighter. For me the expense is justified by the subtle increase in sharpness. It made a difference in my work.