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05-07-2010, 06:29 AM   #1
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645: Teleconverters?

Hi all -

I've done some pretty extensive searches online about this and haven't come up with a verdict yet. My question is partly academic, as I just ordered the damn thing (and will share the results!), but I am wondering if any of you have used the 645 1.4x teleconverter with the longer telephotos... and of course, ask how they performed.

I just bought the 1.4x TC with the hope of using it mainly on my 200mm f/4 FA but also on my 120mm f/4 FA Macro when it's called for.

The TC is billed as "optimized" for the 300mm f/4 but also as compatible with both of my telephotos... any possible explanations as to why that might be?

Is there a lot of sharpness / contrast loss in using the TC?

Thanks for your thoughts and I'll contribute mine as soon as KEH ships my goodies out!

05-07-2010, 07:05 AM   #2
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Hi Andy,

I am hoping to pick up some film I shot with the FA 400mm and the 1.4x converter.

I think the whole optimized with the 300mm bit is from early literature, as some of the other lenses were released after this combination came out. I think this was matched for the A 300mm, but I may be incorrect here.

I will post something when I get my film back.

Yuri
05-07-2010, 07:08 AM   #3
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Thanks for the tip, Yuri - just to be clear, there IS only one 1.4x TC, right? the -A version? I haven't seen anything about FA versions.
05-07-2010, 10:38 PM   #4
D W
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There are two TC's. Both only in A version.

05-08-2010, 05:21 AM   #5
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The other teleconverter is a 2.0X and it is an A version as DW alluded to. To my knowledge there are no FA teleconverters for Pentax 645/N/NII.
05-15-2010, 09:56 AM   #6
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These are 600x400 pixel crops of the photos in the gallery. No post production done, just crops.
The top photo was taken with the Pentax 645 FA 400mm f/5.6 (no cropped https://www.pentaxforums.com/gallery/photo-18493.html)and the bottom photo has the 1.4x converter (no cropped https://www.pentaxforums.com/gallery/photo-18493.html) attached from the same position.
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Last edited by yurihuta; 05-15-2010 at 10:06 AM.
05-15-2010, 10:05 AM   #7
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A couple of closer crops. No post production done, just crops.

Keep in mind these are severe crops and jpgs on top of that.

Top - no converter; bottom - with 1.4x converter.
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05-15-2010, 10:06 AM   #8
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Not sure about you, but I can't tell the difference in quality at all. What about the corners? Are you seeing anything?

I'm headed out with my 1.4x / 200mm f/4 combo today to do some test shots. Results coming soon...!

05-15-2010, 10:11 AM   #9
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Hi Andy, These are not good images to judge the corners I think. I need to photograph more flat walls with newspapers glued to them - kidding. But I am really happy with the FA 400mm and the 1.4x converter. Let us know how your combination works out. The FA 200mm is nice and light! I briefly had one, but by then my lens buying had gotten completely out of hand and I reluctantly sent it back. Yuri

QuoteOriginally posted by andycogbill Quote
Not sure about you, but I can't tell the difference in quality at all. What about the corners? Are you seeing anything?

I'm headed out with my 1.4x / 200mm f/4 combo today to do some test shots. Results coming soon...!
05-17-2010, 12:21 AM   #10
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Hello Youri,

thank you for the images. May I just ask what scanner didi you use? The second crop seems to be limited by the scanner a bit.

Actually - how did you find the manual focusing with the effective f/stop of f/8?
05-19-2010, 04:27 PM   #11
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Hi Yuri,

hope this time my post makes it! I wonder how much different a crop of the 400mm without converter would be compared to the 400mm with converter. One looses quality by cropping, the other by converting. Is the latter better? From your examples, it seems it would be just a bit but by any big margin. What's your take?
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