I initially posted this over on the Pentax Forum, because I am a bit intimidated by the expertise of all the Pros here, but here goes:
Hi all:
Yes, I am an Amateur, but no stranger to big prints from MF negatives. Built my first darkroom in 1959, was making 16"x20" color prints by 1960, using "Kodak Color Print Material Type C" (It didn't even have a name). I used Hasselblad 500C, Pentax 6x7 and 645 cameras. Scanned negatives of those old shots using a Polaroid 4000 dpi 120 Sprintscan yield great 20"x30" prints.
Pentax has a winner here, as I believe the target audience is people like me: serious photographer/print maker, sell enough big (20"x24", 24"x30" and 30"x36" mat and framed) fine art prints every year to allow me to use fine equipment. I wanted to check out all the focus issues I have read here and elsewhere. I used 4 of my 7 accumulated lenses of a shot from my deck looking at the bay. For each lens, focus #1 was at the end of the pier. No2 was mid-pier. No 3 was at house on island ("Almost" infinity), and focus 4 was at infinity, achieved by manually moving the focus ring as far as it would go. 645 lenses do not go past infinity. I checkd the AF 45~85 at 45mm, 65mm, and 85mm. I also checked my manual focus 35mm f3.5, 55mm manual f2.8, and 75mm f2.8 manual. All hand held, f11 at about 1/250 Aperature preferred. ISO 200. No post processing/sharpening. I will try to upload a down sized jpg to show the test scene. The biggest prints I will be making will be 24"x32", limited by my 24" printer. Here is what I found:
1. For all focus points, both MF and AF lenses, when viewed at "print size" which is natively about 22"x 30"@240 dpi, everything looks very vey sharp, and it does not seem like I missed focus. It should make stunning prints that size. At "Actual Pixels" it still looks like I hit focus, but I did not see the detail I thought I would see (however I would never make a print this big). So far using this quick check at one f stop only, the 75mm manual focus is a real gem; probaly best of all of them. The 55mm was either a wee bit softer, or I slightly missed focus, or both. This lens will however be a good performer at "print size" magnifications. I also have the 45mm manual, 80~160 manual and 200mm AF, which I will check tomorrow.
My first shock was half way through testing I filled up a 32 GB card, the only one I have. There were only 24 shots on it! I promptly ordered 3 more cards. I shot DNG RAW; tomorrow I will try the native Pentax RAW, which perhaps uses lossless compression?
I hope I can upload the picture...
Here goes
Dave in NJ
