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12-09-2011, 02:32 PM   #1
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Made in Vietnam FA35 and FA33-55

Hi all,

I'm looking for either a FA35 or the FA33-55 for the 645D. I've seen a few 35mm on eBay where some have "Assembled in Vietnam" etched on the rear of the lens, while others don't.
Are the lenses different in any way? Are the ones made in Japan better quality in any way; better quality control maybe?
I'm looking for a wide angle for landscapes. Any thoughts on these two options is much appreciated.
I'm leaning toward the prime 35 because of its lack of barrel/pin cushion distortion over the zoom. But the zoom is more convenient to use.

Thanks

12-09-2011, 02:50 PM   #2
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Pentax simply changed their factory location: AFAIK they are identical, although some prefer just to have the MIJ versions.

In any case both of these lenses are quite rare! As an alternative you could also consider the A 35mm Also I've heard some negative things about the zoom- see the reviews page!
12-09-2011, 03:57 PM   #3
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I just sold an A 35mm...nothing short of beautiful but I'm not shooting 645 any more and it helped fund my K5 purchase . If I was still shooting 645, I wouldn't leave home without it.
12-09-2011, 06:25 PM   #4
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The issue of Made in Japan vs Not comes up in many hobbies. In watches its a big deal and many pay a lot more for a Seiko, for example, that is marked "Japan" or even better "Nippon" than one that isn't. The fans keep saying that there is no difference because the ISO standards and the yadda-yadda-yadda management are the same. Funny thing, fewer problems with the ones marked "Japan" like misalignment of hands, running too fast out of the box, etc. If given a choice, I will always take Made in Japan over Vietnam, Phillip.'s, or China based on my experience with some rather higher end Japanese watches. Just my $2 worth (inflation).

12-11-2011, 06:29 PM   #5
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The 35A is a fabulous, light weight, sharp lens with minimal distortion. It is also a hell of a lot cheaper than the FA. Given how wide it is, do you really need AF in the first place?
12-12-2011, 07:29 AM   #6
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You're right, at that focal length I'd use hyper-focal focusing and wouldn't usually have the lens in AF. My preference for the FA version was due to how many reviews I've read regarding the variance among used copies of all Pentax's 645 lenses. The consensus appears to be that it's a "crap shoot" to find a good copy of any lens. So, I'm thinking that since FA lenses are newer than A lenses, then I should have a better chance of avoiding bad copies of any focal length if I stick with FA lenses that are close to mint as possible.
I'm new to the Pentax brand with a 645D in the mail. I've never shot a pic with a Pentax camera let alone held a Pentax MF body, so I'm just trying to get the best that I can.
12-12-2011, 07:52 AM   #7
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I would take the reviews of the quality of specific qualities of anyone copy of the 35mm with a grain of salt. Most claims come without an example and from what appear to be pixel peepers. Yet, the 35mm is a popular lens and many 645D shooters are using it. The only consensus about any of the 645D lenses is the quality of the 45mm--I have never seen anyone say they like it. All the other lenses seem to have folks that like them and a few that don't.

I shoot with an A version of the 35mm lens which I really like, not only for the image quality, but the size. I found it a little tricky to get a handle on the focus, but after a little practice, I am very happy with it. If you use the DoF scales on the A or AF lenses, use the index marks for the next largest stop--if shooting at f/11, use the f/8 marks. The format is smaller than 6x4.5 film for which the scales were calculated.
12-13-2011, 06:59 PM   #8
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Yamanobori,

Thanks for your helpful information. Just to make sure I understand you correctly re DOP. When the lens is set to f/11, refer to the marks for f/8 on the DOP scale? So using A or FA lenses on the 645D give shallower DOP than the same lens on a 645N?

I thought since DOP is affected by the f-stop, focusing distance, and focal length. Therefor the DOP for any given lens shouldn't change just because the sensor size is different. A 50mm f/1.4 lens on a FF or cropped-sensored camera will have different angle of views - obviously - due to the cropping characteristics of the body. But that still doesn't seem to change the physical focal length of the lens. OR does it?
So the DOP of the 50mm on either camera should be the same because DOP is affected only on focusing distance, f-stop, and focal length.

Or am I misunderstanding your point?

Frank

12-14-2011, 01:55 AM   #9
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35mm

In fairness to Yamanbori, this late at night , I am too lazy to back up my findings with examples, but............ My A35 is also wider than my FA35, and i quite like the extra millimeter or so it provides. Also the FA is more prone to flare.....

In a perfect world i would sell them both and use the proceeds towards a 25MM..............
12-14-2011, 01:58 AM   #10
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Frank,

I think you are right in what you say about the principles, i.e. that Depth of Field is determined only by f-stop, focal length and subject-sensor distance; that would indeed imply that actual sensor size (or film format) would not affect this if those other variables were constant, even though the angle of view changes.

However, the reason why what Yamanobori says is good practice is slightly different; the high resolution of the 645D means that you can print very large (or indeed view digital files very close and expect detail to be visible) - this means that losses of resolution or sharpness can be spotted on close inspection. If you want the areas that appear to be in focus (via depth of field) to deliver sharp results over a wide range of subject-sensor distances - and to do so on such close inspection - then you need to take a more cautious approach to estimating the depth of field in the first place. Remember that depth of field markings are somewhat arbitrary - they depend on assumptions about the point at which you believe a picture goes from being acceptably sharp to unaccetably sharp. There is nothing absolute or magical about that point - it is simply a judgement call someone has made (there are conventions about this, but they are not absolute). The advent of high resolution cameras like the 645D is that you can see failings more readily, so you may wish to be more cautious when shooting. Using the depth of field markings for an aperture one stop wider than previously represents this caution, or, put differently, using an aperture one stop narrower in any given situation (in fact some people would say one stop of adjustment in this way is not enough - and advocate two stops).

So, in short, I agree with Yamanobori's rule of thumb, even if I am not sure I agree with the reasons given (and would even go further)!

By the way, making such adjustments from depth of field markings on lenses is only a rule of thumb. You can be more precise by calculating circles of confusion and comparing this data to the pixel pitch of a sensor - but other people will be better qualified than I am to advise on this!
12-14-2011, 07:15 AM   #11
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Actually, DoF is determined by focal length, distance, f-number, and the permissible circle of confusion for the format. So as the format increases, so does the permissible circle of confusion, which defines sharpness. The smaller the format, the great the magnification to a print size and so the circle of confusion will also go through a larger magnification and what was once an acceptable CoC for a larger format, will now be unacceptable for a smaller one. Since it is all geometric, the shift in the DoF is directly related to crop factor. The crop factor is 1.36 for the 645D. 1.36 is very close to the square root of 2 (1.4), which is one stop--remember DoF is related to the f-number which is what is creating the permissible circle of confusion.

This is not anything new except more folks are using optics on formats that they were not designed for. And it is actual, you will see the change--it will be subtle, but it is real. Zeiss has a paper somewhere on the web that says the same thing. Like I said, this is not anything new. But you are welcome to test and see what you are happy with--sharpness is subjective.

Last edited by Yamanobori; 12-14-2011 at 07:22 AM.
12-14-2011, 07:16 AM   #12
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QuoteOriginally posted by FrankC Quote
Yamanobori,

Thanks for your helpful information. Just to make sure I understand you correctly re DOP. When the lens is set to f/11, refer to the marks for f/8 on the DOP scale? So using A or FA lenses on the 645D give shallower DOP than the same lens on a 645N?
That is right.
12-14-2011, 07:36 AM   #13
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BTW, none of this has to do with print size nor sensor resolution--just as DoF never changes when shooting with Tech Pan or TriX. In fact, print size is not limited by pixel resolution. It is always a relative problem. The bigger the print, the larger the viewing distance. An 8x10 print at 300dpi and viewed at 10 inches will look exactly the same at 16x20 at 150dpi viewed at 20 inches. I often print with a 44 inch printer up to 12 feet long and all kinds of image files. The idea of correct viewing distance works really really well. I will get a few folks (artists, scientists, and museum curators) through my door thinking there are limits to print size. None of them leave believing that.

I have one of the greatest jobs in the world and get to do all kinds of stuff most folks don't. I also have a very technical background in imaging and have the added bonus of being well versed in my field. So I understand the theory AND I am applying it. So this is not just an academic argument you so often find on the web.
12-14-2011, 09:50 AM   #14
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The science behind all of this is very interesting. Thanks for the education, I really do appreciate it.
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