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12-01-2011, 01:11 PM   #31
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QuoteOriginally posted by Lowell Goudge Quote
more often than not, birds move so unexpectidly that they are just a blurr at the edge of the frame.
So true.

I am normally happy if I found the bird again in the viewfinder as it is constantly leaving it ... (at such long FLs). That's actually an advantage a FF viewfinder would give me: keeping the bird longer in VF

Also, I am wondering how any current EVF could be fast enough to this challenge.

In comparison, I found it surprising that the K-5's phase AF with 1.7x TC was fast enough to aquire focus. It's really not such a bad system ... Of course, the 1.7x works like a focus limiter helping in this case. So, I actually prefer it over the 1.4x TCs.

12-01-2011, 01:38 PM   #32
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QuoteOriginally posted by falconeye Quote
So true.

I am normally happy if I found the bird again in the viewfinder as it is constantly leaving it ... (at such long FLs). That's actually an advantage a FF viewfinder would give me: keeping the bird longer in VF
only on the assumption that you did not attempt to fill the viewfinder by creeping up on the bird trying to frame it in the bigger full frame
QuoteQuote:

Also, I am wondering how any current EVF could be fast enough to this challenge.
NOT i wouldnt even want to think about it, my experience with bridge cameras is the shutter lag is so bad, you need to press the shutter before the bird lands to have a chance of getting it in frame, sitting on the branch. the one advantage of small sensor EV cameras, is the relitively fast optics. My Kodak DX7590 is an F3.2 at maximum focal length, with a 35mm equivelent of 360mm. it sure weighs a lot less than any one's 300/2.8
QuoteQuote:

In comparison, I found it surprising that the K-5's phase AF with 1.7x TC was fast enough to aquire focus. It's really not such a bad system ... Of course, the 1.7x works like a focus limiter helping in this case. So, I actually prefer it over the 1.4x TCs.
I really like the AF TC. I have used it since my PZ-1 in 1991, and much of this has been with the K300/4 Then, I was somewhat light limited, unless I used flash, due to the low ISO of films, but my experience is that even the K7 at 1600 was a s good as film at 400 so it does get a lot more use now, and with the K5 it is even better.
The fact that you are in Semi Auto Focus because it only has about 7mm effective focus throw, actually works well for shooting through a maze of branches.
12-01-2011, 09:53 PM   #33
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QuoteOriginally posted by falconeye Quote
... sometime use the Pentax 1.7x TC with a Sigma 500/4.5 APO, a combo which gives me AF. Below is a shot I took from outside a park during a flight show, i.e., I was much more far away than the visitors in the foreground. It's slightly cropped to 1000mm (1540mm equivalent FoV).
It is very impressive shot, if it was taken hand held. The maximum FL rig I've ever used so far was 800mm (1200mm on APS C). Recently I acquired a very rare Tamron Adaptall-2 flat-field 2X 200F TC for my Tamron 400/4. I haven't had a chance to try it outside, but that's what it is capable of from 6-7m (yards) distance (MF, live view, tripod indeed), if you can suppress a tremor:
The power of 800mm: Pentax SLR Talk Forum: Digital Photography Review
QuoteOriginally posted by Lowell Goudge Quote
I really like the AF TC. I have used it since my PZ-1 in 1991, and much of this has been with the K300/4 Then, I was somewhat light limited, unless I used flash, due to the low ISO of films, but my experience is that even the K7 at 1600 was a s good as film at 400 so it does get a lot more use now, and with the K5 it is even better.
The fact that you are in Semi Auto Focus because it only has about 7mm effective focus throw, actually works well for shooting through a maze of branches.
QuoteOriginally posted by falconeye Quote
In comparison, I found it surprising that the K-5's phase AF with 1.7x TC was fast enough to aquire focus. It's really not such a bad system ... Of course, the 1.7x works like a focus limiter helping in this case. So, I actually prefer it over the 1.4x TCs.
For some reason this impressive piece of optics (Pentax 1.7X AFA) have never worked well for me. When I lost a few really good opportunities I almost stopped using it. It is not a quickest thing to focus either. Works OK when used on a tripod. But AF is still inconsistent and unpredictable a bit. Most likely it's me not the AFA, though. 1.4X AF TCs work better for me.
BTW: If you care, there are a few field shots taken with FA*300/4.5 and three different TCs prior to my humble testing:
Vivitar Series1 1.4X AF:
A few birds from today walk with FA*300/4.5 and 1.4x TC: Pentax SLR Talk Forum: Digital Photography Review
Sigma APO 1.4X EX:
Sanitizing ugliness. Beware: some graphic images inside.: Pentax SLR Talk Forum: Digital Photography Review
Sigma APO 1.4X EX DG:
FA*300/4.5 + Sigma APO 1.4x EX DG TC combo: Pentax SLR Talk Forum: Digital Photography Review
QuoteOriginally posted by Lowell Goudge Quote
Shake reduction is great, as far as it goes...
There is a very interesting study accomplished by MightyMike. He claims that Pentax SR system has a flaws at longest focal lengths and it's better to set up much lower FL (100-200mm) for longer lenses (500-600mm).
A SR Study, Super-Telephoto Problems, Amazing!: Pentax SLR Talk Forum: Digital Photography Review
Of course you can do it only when using MF glass. When using TCs it is a favorable thing, because the camera doesn't read TC presence and doesn't adjust higher FL accordingly. Personally I found that my shots are noticeably better when lens FL is no longer than 400mm (420mm to be exact). That's maybe where my trouble with 1.7X AFA is. I may not hold the 510mm steady enough. However, I prefer to shoot hand held.
12-02-2011, 02:52 AM   #34
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QuoteOriginally posted by Greyser Quote
There is a very interesting study accomplished by MightyMike. He claims that Pentax SR system has a flaws at longest focal lengths and it's better to set up much lower FL (100-200mm) for longer lenses (500-600mm).
A SR Study, Super-Telephoto Problems, Amazing!: Pentax SLR Talk Forum: Digital Photography Review
Of course you can do it only when using MF glass. When using TCs it is a favorable thing, because the camera doesn't read TC presence and doesn't adjust higher FL accordingly. Personally I found that my shots are noticeably better when lens FL is no longer than 400mm (420mm to be exact). That's maybe where my trouble with 1.7X AFA is. I may not hold the 510mm steady enough. However, I prefer to shoot hand held.
My shot was hand-held but with the lens supported by the park's fence.

Following Mike's advice has a problem. Lowering FL from, say 800 to 400 halfs SR movements, reducing the improvement to 1 stop or less. Lowering to 200 would only leave 1/2 stop improvement or less. You can then switch SR off.

I used SR at 800mm and I didn't get the impression of flaws. Moreover, I measured SR efficiency with the K-7 and saw no sign of a problem at 300mm.

12-02-2011, 08:38 AM   #35
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QuoteOriginally posted by falconeye Quote
Following Mike's advice has a problem. Lowering FL from, say 800 to 400 halfs SR movements, reducing the improvement to 1 stop or less. Lowering to 200 would only leave 1/2 stop improvement or less. You can then switch SR off.

I used SR at 800mm and I didn't get the impression of flaws. Moreover, I measured SR efficiency with the K-7 and saw no sign of a problem at 300mm.
Personally I have better results at 400mm compared to 500mm. However, it might be a matter of poorer handling. When using TC the SR compensates for the "official" primer lens FL, not adjusting to compensate added by TC FL. So, according to Mike I have favorable benefits; according to you the 510mm shots are under compensated.
12-02-2011, 10:40 AM   #36
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I always felt that there should be the ability to compensate for shake reduction just like ff/bf because depending on user technique and each lens and it's own center of gravity and nodal point being different, it is somewhat of a compromise. Personally, at least with the K7 it seems very well matched for my shooting technique and my K300/4 plissť 1.7x, at least as evident by my heron shot at 1/40 free standing and hand held. I don't claim I can do this every time, and as noted earlier, aside from some herons, most of my subjects don't stay still that long, but it is possible. I have not had the K5 long enough to really say if it is better or worse, but I think the K7 is better than the K10 at 500mm
12-02-2011, 11:53 AM   #37
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Thanks to the original poster. Real world tests should never be compared to the ramblings of the lab boys. They are invariably two different things. The numbers don't mean a thing without context. And there is no context for understanding the numbers, unless you're shooting 2D test patterns. I don't sell many photo's of 2D test patterns, there doesn't seem to be much of a market.
12-02-2011, 02:16 PM   #38
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QuoteOriginally posted by normhead Quote
Thanks to the original poster. Real world tests should never be compared to the ramblings of the lab boys. They are invariably two different things. The numbers don't mean a thing without context. And there is no context for understanding the numbers, unless you're shooting 2D test patterns. I don't sell many photo's of 2D test patterns, there doesn't seem to be much of a market.
Not a problem. As I said somewhere above, I feel obligated to share my findings with others. I've learned a lot from others and I'd like to pay my debts back in the same "currency" as when I used to borrow a bits of knowledge, image samples, tiny lens hints here and there. it's not very common to own 6 TCs at once (actually I have more, but they are different story). And it's just happened that when I was looking for the first 1.4X a couple month ago I couldn't find anything but the Vivitar. Then, when I got an opportunity to add Tamron 1.4X and coming Photomaster 1.7x for much below eBay prices I couldn't resist. That's how it goes usually. And I got Sigma APO EX kind of for free, but paid $200 for the Sigma APO EX DG.
BTW: I also plan to shoot out the FA*300/4.5+ 1.4X TC, Sigma 100-300/4+1.4X TC, and DA*60-150/4+1.7X TC to match the first two. That might be another fun

12-04-2011, 02:37 AM   #39
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Promaster 1.7X Z AF is added to my TC collection

There are a few samples taken with FA*300/4.5 and Promaster 1.4X Spectrum 7 Z AF TC here:
510mm: Promaster 1.7X Spectrum 7 Z AF TC: Pentax SLR Talk Forum: Digital Photography Review
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