soft focusing problems with FA 45mm 645n

[ian_morgan1]

I have a problem with a pentax 645n camera and a 45mm FA lens i own.

The lens was bought used off ebay but has no signs of being touched

at all , yet it seem to have odd focusing problems which i can not

work out if it is the lens or the camera! I have owned a 645 and had

no problems with sharpness at any setting.

 

I usually shoot landscapes on velvia 50. i set the camera at between

f16 and f22 at 1/2 - 1/15. I use a manfrotto 055 tripod at all times

and also a hoya hmc 81b filter along with a sigma ex circular

polariser on all 3 lenses.

 

many of my films are coming back very slightly soft or with odd zones

of unsharpenss in the horizon at the sides of the frame. I have a

75mm fa and a manual 55mm which do not seem to suffer from the

problem. I have however had the same problem (but only once or

twice) with the 75mm also but NEVER the 55mm! Any ideas???!

[danny_wong2]

Try the brick wall or chian link fence test and then you can see where the out of focus area is.

 

If you have a second P645 then try it on the second body as well.

 

Most likely it is the lens. I never has any problem with my 35,45,55FA's

[rvalois]

Hi ian ...

 

I think Danny has a good idea ... try it out and see the results.

 

I shoot weddings and use the AF 75mm, AF 45mm and AF 80-160mm and have not encountered any problems since I purchased the 645N and these lenses.

 

Good luck !

 

Ray

[cliff_lesergent]

You may be experiencing a problem with film flatness (or lack thereof). The 645N can be somewhat prone to this problem because it has narrower spacing between frames. I've noticed this problem on a number of images taken with the my 645N.

 

I believe you'll find a few threads in this forum that go into this topic in more detail.