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Forum: Welcomes and Introductions 04-30-2019, 07:16 AM  
Hello from Sweden!
Posted By JonVdG
Replies: 13
Views: 572
Hello from New York and welcome to the forum. Sorry to hear about your equipment being stolen. I hope your new camera is treating you well - Sweden is a beautiful country and worthy of some good Pentax glass.

Cheers,
Jon
Forum: Pentax Medium Format 03-25-2019, 08:21 AM  
200mm f/4 645 with 1.4x teleconverter?
Posted By JonVdG
Replies: 7
Views: 1,100
Thanks, Richard. It sounds like you might have had a bad copy of the A 200mm. My copy is sharp from corner to corner at f/4 on the 645D. My reference points are the Leica 135mm Elmar, Minolta 200mm APO, and Nikon 70-200mm AF-S VR. I've read that the A and FA have similar (identical?) optical formulas but can't confirm this. Perhaps I'll find an inexpensive copy of the TC and just see how it works out.
Forum: Pentax K-1 02-07-2019, 03:15 PM  
Picking up a used K-1 tomorrow...what should I look out for?
Posted By JonVdG
Replies: 13
Views: 1,233
Also check for excessive sensor dust. This can be a serious issue. While a few specks here and there might be easy to clean, or deal with in post processing, a lot of particles or unremovable particles can make the purchase not worthwhile. I recently purchased a new Panasonic camera that had two pieces of unremovable dust - even a wet swab didn't work. I returned it for a replacement. Apparently, dust can become lodged between the filter and sensor so that only the manufacturer can repair it. Take two shots of a clear sky (or similar) - one at the f-stop you are most likely to use most of the time, and one stopped down to at least f/10. This will give you an idea of how dirty it is. Good luck.
Forum: Pentax Film SLR Discussion 02-07-2019, 02:49 PM  
Underexposed, underdeveloped, or incorrectly scanned?
Posted By JonVdG
Replies: 28
Views: 1,774
To my eyes, it doesn't look like an exposure issue. I would guess a development or scanning issue. However, depending on your workflow, you may still have a nicely developable file. In your image processor, a couple minutes with the tonal curve would do a lot for enhancing contrast if that's what you're looking for. I've had similar issues where the lab doesn't get something right but often still leaves me with a high resolution and fairly malleable file. Sorry I can't be of more help.
Forum: Pentax Medium Format 02-07-2019, 01:18 PM  
Newly purchased a 645 A 150/ 3,5 lens and does not focus
Posted By JonVdG
Replies: 4
Views: 775
Hi Dennis, I think you're right - it's the lens. Without even turning on the 645D, you should be able to see the focus change in the viewfinder as you turn the focus ring. I don't believe there are any settings in the camera body that you need to adjust to allow the lens to manually focus properly. Good luck.
Forum: General Photography 02-07-2019, 05:48 AM  
Smc coating vs hd coating
Posted By JonVdG
Replies: 12
Views: 1,318
Thanks, I suspected exposure might be influencing my perception of tonality. As a matter of curiosity, I just purchased an older Pentax SMC UV filter to test against my modern multicoated Hoya and B&W filters. I don't expect to see any dramatic differences, but one never knows.
Forum: Pentax Medium Format 02-07-2019, 05:43 AM  
200mm f/4 645 with 1.4x teleconverter?
Posted By JonVdG
Replies: 7
Views: 1,100
Thanks, that's good to know. Seems like it could be a decent, compact solution if I don't want to pack the 300mm.
Forum: General Photography 02-06-2019, 01:18 PM  
Smc coating vs hd coating
Posted By JonVdG
Replies: 12
Views: 1,318
Ignoring sharpness for a minute and just considering tonality, I prefer the SMC coating in the OP's test. Making the same comparison between my SMC 645 A lenses and my Leica M lenses leaves me impressed with just how right Pentax got their SMC coatings from the start.
Forum: Pentax Medium Format 02-05-2019, 05:49 PM  
200mm f/4 645 with 1.4x teleconverter?
Posted By JonVdG
Replies: 7
Views: 1,100
Just wondering if anyone has tried this combination and if so, what are your thoughts on sharpness? I've found the 200mm SMC-A to be extremely sharp from edge to edge, even wide open. That's made me tempted to buy a 1.4x TC for infrequent use, as an alternative to carrying the 300mm f/4 or 150-300mm FA f/5.6. I'll primarily be using it for landscape work on the 645D.
Forum: Pentax Medium Format 01-31-2019, 08:44 PM  
Pentax FA 645 lenses with hard stop at infinity?
Posted By JonVdG
Replies: 8
Views: 747
Thanks, that definitely helps! It appears the 75mm does do a hard stop at infinity but the 150mm might drift a little beyond it.
Forum: Pentax Medium Format 01-31-2019, 05:03 PM  
Pentax FA 645 lenses with hard stop at infinity?
Posted By JonVdG
Replies: 8
Views: 747
Thanks, this helps a lot. I've seen lenses from other manufacturers behave the same - ever so slightly past the center of the infinity mark, and I really had to do a close examination to notice. All of these had correct infinity focus at the hard stop so I suspect the Pentax does as well. Leica lenses seem to be consistently perfect at the center of the infinity mark, and most of my old Nikkor MF lenses were as well. Again, thanks, I think I'll buy the FA model and see if I can confirm it.
Forum: Pentax Medium Format 01-30-2019, 07:19 PM  
Pentax FA 645 lenses with hard stop at infinity?
Posted By JonVdG
Replies: 8
Views: 747
Thanks for your comment. What I was referring to was the quality of the materials used for compensation. Sorry, should have been more clear about that. I have used dozens of fixed focal length lenses and zoom lenses, that hard stop at infinity, in temperatures from -40 to +110 degrees F, and not one has ever missed focus (other than for user error). My experience has been with lenses from Leica, Nikon, Tokina, Minolta, and Sony. Temperature compensating materials have been in use for hundreds of years in various types of instruments and it seems like photographic lenses have no problems with extreme temperatures so I assume manufacturers have taken advantage of this, except when trying to keep their costs low. However, I could imagine that fast autofocus mechanisms with a lot of torque that are trying to keep up with today's continuous AF demands might benefit from not constantly hitting their physical limit. One of my Tokina zoom lenses was constantly slapping its hard stop and it just seemed like that might not be a good thing over a long period of time.

It appears the FA 75mm has a hard stop at infinity, but I'm just guessing based on photos of the lens that never show its focus mark reaching beyond the center of the infinity symbol. Can anyone confirm this?
Forum: Pentax Medium Format 01-29-2019, 09:25 AM  
Pentax FA 645 lenses with hard stop at infinity?
Posted By JonVdG
Replies: 8
Views: 747
Thanks, Bob. I'm beginning to suspect that most if not all of the FA lenses move beyond infinity. As you mentioned, this is probably to compensate for the thermal expansion, and in my understanding this is done when lower quality materials are used in the lens (many manufacturers do this). However, I hadn't thought about the continuous AF factor. In any case, I might need to use manual focus lenses only for my application, which is fine because I appreciate the high build quality of Pentax's older 645 lenses. Still, if anyone finds a FA lens that does hard stop at infinity, please let me know. Thanks again.
Forum: Pentax Medium Format 01-28-2019, 10:23 AM  
Pentax FA 645 lenses with hard stop at infinity?
Posted By JonVdG
Replies: 8
Views: 747
Hello, I'm a newbie here and I have a specific need for lenses that have a hard stop at infinity, meaning lenses that are properly focused at infinity when the infinity symbol is aligned with the focus distance mark at the end of focus ring rotation. This was always the case with my Leica M lenses and older Pentax SLR manual focus lenses. It also appears to be true for manual focus Pentax 645 lenses. Do any of the 645 FA lenses hard stop correctly at infinity? If you've worked with one that does or does not, I would greatly appreciate your observations.

If I've missed something in the database that has this information, or if someone knows of an external resource about this, please let me know. Thanks for your help!
Forum: Welcomes and Introductions 01-28-2019, 10:08 AM  
Greetings from Long Island!
Posted By JonVdG
Replies: 5
Views: 339
Hello, I just joined the forum with the primary motivation of reading and contributing to the medium format camera and lens reviews. I've shot nearly every format, from Micro Four Thirds to 6x7 over many years. Most of my photojournalism work over the last decade has been APS-C. Today, I am shifting to medium format for some documentary work and I couldn't be more excited. Like any camera system, it has its affordances and limitations but I've learned how to develop workarounds and be thankful for having access to such a beautiful sensor / film. I hope to make some new friends here and learn from your experiences.

Cheers,
Jon
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