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11-28-2014, 09:00 AM   #1
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focus issues

Hello, I hope I am in the right place, I couldnt find exactly the right topic in the search box. So here is my problem; I just got back a roll of color film and every pic is out of focus, the camera is a used ME, and the lens is a used 28mm wide angle, this is the first roll put through this camera. Is it more likely that the camera is off or the lens? Both appear in very good condition. I use glasses so a pic or three would not surprise me but the entire roll? They all seem to be about the same level of out-of -focus also. All the pics were taken at what the lens would say is "infinity", no closeups. I paced off ten feet and when checked, the distance agreed with the focus in the viewfinder and the distance marked on the lens focus ring. Any thoughts? Thanks, Steve

11-28-2014, 09:30 AM - 1 Like   #2
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Welcome.
What typical f/ and shutter speed were you using?

This info might help to differentiate between focus blur and camera shake

If the shutter speed was too low, you might have camera shake.
11-28-2014, 10:05 AM - 1 Like   #3
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Welcome to the Pentax Forums!

wombat2go covered the most common cause of soft photos, camera motion. I will continue with a few more comments.

A few things to consider:
  • Film must be flat. Is there any chance the pressure plate on the inside of the film door is missing?
  • If you wear glasses, you should use them when shooting with an SLR, either that or fit an accessory diopter adapter to the viewfinder. In order to accurately focus, you must be able to see a sharp image of the focus screen.
  • Focus with a wide angle is a more difficult than with longer lenses. This is offset somewhat by greater apparent depth-of-field in general shooting, but out of focus is still out of focus.
  • It is possible that your camera's optical path is no longer proper
    • Mirror angle
    • Focus screen calibration
    • Mount flange distance
    All of these should remain the same over the life of the camera, but physical damage or a botched service attempt may result in any or all being wrong.
I hope this helps.

Oh, and one final consideration. The quality of commercial scans/prints is quite variable.


Steve
11-28-2014, 10:59 AM   #4
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QuoteOriginally posted by wombat2go Quote
Welcome.
What typical f/ and shutter speed were you using?

This info might help to differentiate between focus blur and camera shake

If the shutter speed was too low, you might have camera shake.
Off hand I dont know, the ME automatically sets shutter speed, and these pics were all taken in good sunlight. However this is not camera shake, they are visibly soft focus. I am thinking its the camera body, I have 6 or 8 K1000's and Spotmatics that never fail. Perhaps it would be easiest to mix and match body and lens and run test rolls to isolate the defective part .

---------- Post added 11-28-14 at 01:03 PM ----------

QuoteOriginally posted by stevebrot Quote
Welcome to the Pentax Forums!

wombat2go covered the most common cause of soft photos, camera motion. I will continue with a few more comments.

A few things to consider:
  • Film must be flat. Is there any chance the pressure plate on the inside of the film door is missing?
  • If you wear glasses, you should use them when shooting with an SLR, either that or fit an accessory diopter adapter to the viewfinder. In order to accurately focus, you must be able to see a sharp image of the focus screen.
  • Focus with a wide angle is a more difficult than with longer lenses. This is offset somewhat by greater apparent depth-of-field in general shooting, but out of focus is still out of focus.
  • It is possible that your camera's optical path is no longer proper
    • Mirror angle
    • Focus screen calibration
    • Mount flange distance
    All of these should remain the same over the life of the camera, but physical damage or a botched service attempt may result in any or all being wrong.
I hope this helps.

Oh, and one final consideration. The quality of commercial scans/prints is quite variable.


Steve
Thank you for the reply. Wide angles are hyper sensitive about focus, I learned this just now working the lens without film, I also notice I need to be looking through dead center of the view finder, any drift left or right and focus changes. I thunk mix and match with lenses and bodies will be easier to narrow down the problem. Thanks, Steve


Last edited by film-or-die; 11-28-2014 at 11:13 AM.
11-28-2014, 12:06 PM - 1 Like   #5
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QuoteOriginally posted by film-or-die Quote
Perhaps it would be easiest to mix and match body and lens and run test rolls to isolate the defective part .
Good idea, you can do it by changing one partly exposed test roll between bodies if you keep track of the frame numbers.

There is also a way you can directly check infinity focus on the ME by using clear plastic ( from a shirt box etc) covered with 3M magic tape toward the lens side and cut to fit on the shiny slides as a ground glass.
But it requires a loupe of about 8X

The 28mm lens when stopped down to f/11 and set to infinity, has a depth of field down to about 2 metre ( 6 foot) , so focus should not be as critical as with say a longer standard lens.
11-28-2014, 12:10 PM - 1 Like   #6
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QuoteOriginally posted by stevebrot Quote
Welcome to the Pentax Forums!

wombat2go covered the most common cause of soft photos, camera motion. I will continue with a few more comments.

A few things to consider:
  • Film must be flat. Is there any chance the pressure plate on the inside of the film door is missing?
  • If you wear glasses, you should use them when shooting with an SLR, either that or fit an accessory diopter adapter to the viewfinder. In order to accurately focus, you must be able to see a sharp image of the focus screen.
  • Focus with a wide angle is a more difficult than with longer lenses. This is offset somewhat by greater apparent depth-of-field in general shooting, but out of focus is still out of focus.
  • It is possible that your camera's optical path is no longer proper
    • Mirror angle
    • Focus screen calibration
    • Mount flange distance
    All of these should remain the same over the life of the camera, but physical damage or a botched service attempt may result in any or all being wrong.
I hope this helps.

Oh, and one final consideration. The quality of commercial scans/prints is quite variable.


Steve
Steve made an interesting point about the variation in quality from the commercial developers/printers. Take a close look at your film to see if the negatives are also out of focus.... ;-)


Bob
11-28-2014, 05:14 PM   #7
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QuoteOriginally posted by woodywesty Quote
Steve made an interesting point about the variation in quality from the commercial developers/printers. Take a close look at your film to see if the negatives are also out of focus.... ;-)


Bob
What a great idea, but lab i used doesnt send back the negatives, thats on me for not doing my homework. I will try splitting a roll between the 28mm lens and a known shooter, a find a better lab. Has any of you used the adjustable diopter? 2 of my russian cameras have them built in but I have never used an add-on type. Also thank you all for the ideas! Steve
11-28-2014, 06:07 PM   #8
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Umm. The lab doesn't send back the negs? That's unbelievable, they are your property, your physical property, and your intellectual property. To me they are keeping the negs either to exploit them at a later date (are you Vivianne Mayer?) Or to conceal evidence of their incompetence, which may explain the out of focus prints.

Change to a different lab.

11-28-2014, 07:51 PM   #9
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QuoteOriginally posted by Bagga_Txips Quote
The lab doesn't send back the negs? That's unbelievable, they are your property, your physical property, and your intellectual property.
But becoming a more common occurrence. I recently read a post on another forum where a professional photographer was incensed that their lab, suddenly and without notice, started to return only prints, no negatives. As you state the negs are intellectual property and not returning them is unconscionable. The response from the lab in that story was that they did not think anyone used the negs anymore and they were destroyed after printing.

To the OP: I doubt the lab has any intention of making use of your negatives, most likely it is just a cost savings step by someone who has no clue. I agree with Bagga_Txips, change to a different lab and have the discussion with them up front about what happens to the negatives.
11-29-2014, 06:41 AM   #10
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QuoteOriginally posted by Bagga_Txips Quote
Umm. The lab doesn't send back the negs? That's unbelievable, they are your property, your physical property, and your intellectual property. To me they are keeping the negs either to exploit them at a later date (are you Vivianne Mayer?) Or to conceal evidence of their incompetence, which may explain the out of focus prints.

Change to a different lab.
Many labs now dont send back negatives, what you get is a disk with the prints on it along with paper copies of the photos. This is true at least at the cheap end of the lab spectrum. I have already found a several labs that return negs. I did learn that some labs think their processing is worth its weight in gold, must be geared to the pro photographer. Also, the cheap labs are pretty upfront about whether or not they return negs. I rarely shoot color anymore anyway, its no fun (i prefer the hands on approach and color cant be done at home, not my home anyway) so sending film out is rare for me.
11-30-2014, 09:24 AM   #11
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QuoteOriginally posted by film-or-die Quote
I also notice I need to be looking through dead center of the view finder, any drift left or right and focus changes.
I think you may have found the source of your problem. Yes, wide angle lenses are definitely more difficult to attain critical focus with (everything is so small in the viewfinder), but the sentence quoted above might indicate significant field curvature. Mixing lenses a bit on the camera should help you figure out what is going on.

QuoteOriginally posted by wombat2go Quote
There is also a way you can directly check infinity focus on the ME by using clear plastic ( from a shirt box etc) covered with 3M magic tape toward the lens side and cut to fit on the shiny slides as a ground glass.
But it requires a loupe of about 8X
As noted by wombat2go, you can actually test the focus accuracy without film if you have some tape (scotch-type, the kind that looks sort of frosted), a flat surface with fine print as a focus target, and a tripod. This works at any focus distance, not just infinity. With the shutter open in "B" mode, the lens should project an image on the surface of the tape at the focal plane. That focus should agree with the focus through the viewfinder. A junk focus screen across the film frame can be used as well. As he noted, a magnifying loupe is very helpful for this task. Likewise, a loupe is pretty much essential for evaluating sharpness on the negative as well. The inexpensive 8x "Agfa"-type loupe is adequate. (http://www.freestylephoto.biz/112824-Arista-8x-Loupe)


Steve

Last edited by stevebrot; 11-30-2014 at 09:34 AM.
12-01-2014, 05:50 AM   #12
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QuoteOriginally posted by stevebrot Quote
I think you may have found the source of your problem. Yes, wide angle lenses are definitely more difficult to attain critical focus with (everything is so small in the viewfinder), but the sentence quoted above might indicate significant field curvature. Mixing lenses a bit on the camera should help you figure out what is going on.


As noted by wombat2go, you can actually test the focus accuracy without film if you have some tape (scotch-type, the kind that looks sort of frosted), a flat surface with fine print as a focus target, and a tripod. This works at any focus distance, not just infinity. With the shutter open in "B" mode, the lens should project an image on the surface of the tape at the focal plane. That focus should agree with the focus through the viewfinder. A junk focus screen across the film frame can be used as well. As he noted, a magnifying loupe is very helpful for this task. Likewise, a loupe is pretty much essential for evaluating sharpness on the negative as well. The inexpensive 8x "Agfa"-type loupe is adequate. (Arista 8x Loupe | Freestyle Photographic Supplies)


Steve
I had to look this one up, I have never heard of "field curvature" before. Thank you for that info. I looked at a couple of basic articles about the aberration, but none mentioned wide angle lenses. Is this more common with wides? I had the problem with a 28mm budget Rokinon. Also, to be clear, as I was focusing I was watching the slip image, it would change as I moved my eye around, is this the same thing? I this is a rookie question, I apologize, I never encountered this problem before. Thanks, Steve
12-01-2014, 07:19 AM   #13
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QuoteOriginally posted by film-or-die Quote
Hello, I hope I am in the right place, I couldnt find exactly the right topic in the search box. So here is my problem; I just got back a roll of color film and every pic is out of focus, the camera is a used ME, and the lens is a used 28mm wide angle, this is the first roll put through this camera. Is it more likely that the camera is off or the lens? Both appear in very good condition. I use glasses so a pic or three would not surprise me but the entire roll? They all seem to be about the same level of out-of -focus also. All the pics were taken at what the lens would say is "infinity", no closeups. I paced off ten feet and when checked, the distance agreed with the focus in the viewfinder and the distance marked on the lens focus ring. Any thoughts? Thanks, Steve
Hold the phone! I just discovered that my lens is broken!!!, the aperture doesnt work, so its shooting wide open. No wonder the pics are out of focus. Dammit. Thank you all for the advice just the same.
12-02-2014, 01:46 AM   #14
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What typical f/ and shutter speed were you using?

12-02-2014, 08:12 AM   #15
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QuoteOriginally posted by film-or-die Quote
I looked at a couple of basic articles about the aberration, but none mentioned wide angle lenses. Is this more common with wides?
Field curvature is not as as big a problem with modern lenses, but it used to be common with 28mm and wider lenses for 35mm film. Flat field was a selling point and differentiated premium from consumer-grade wide angles. Usually it would result in distinct softness in the corners, but acceptable performance over the remainder of the frame. What you described is more severe and is likely the result of a botched lens repair (element missing or assembled backward) or a very deficient design.

I read your last comment regarding the aperture. It looks like you will be shopping for a replacement lens. I would suggest one of the K-mount Vivitar 28mm of similar vintage to your camera. They are above average optically (better than the Pentax-M 28/2.8) and inexpensive. See the reviews on this site and this page by Robin Parmar detailing the Viv's variants:

Great Vivitar 28mm Bestiary

I own and can recommend the Komine-made "K02" variant (reviews). I can also recommend the Tamron (Adaptall-2) 28/2.5 (02B) (reviews).


Steve

Last edited by stevebrot; 12-02-2014 at 08:33 AM.
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