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04-14-2016, 12:15 PM - 3 Likes   #1
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DA*60-250 with stacked HD DA 1.4 TC and F1.7 AF adapter stacked to get to 600mm

K-3 and stacks HD DA 1.4TC and F1.7 AF adapter.

250 x1.4x1.7 gives me pretty much 600mm

One last reach experiment... after getting pretty much stellar results with the DA*200 ƒ2.8 and stacked TCs I decided to test my reach options. The A-400 and 1.7 which would give me 680, was a pretty dismal failure. I had trouble locking focus (and I had great light) and the best images weren't good enough. So after completing that, I realized I hadn't tried stacking with the DA* 60-250. So back out again.

I got far fewer keepers and often had considerable trouble locking focus, as much as with the A-400, the difference being, when I did lock focus the images were good.







So from my perspective, this becomes the poor man's way to get to 600mm ƒ6.7. Really, not to shabby.

I guess I could point out that some have sold their Pentax gear and bought whole new systems to get to 600. And with full AF I'm sure those systems are more functional, but if you're on a budget and you own a DA* 60-250, this could be for you. I'd love to be able to try it out with a DA*300, also an ƒ4 lens. I would expect similar results, similar trials getting images and similar joy with the results when successful.

714mm and ƒ6.7 would not be too shabby, with this kind of IQ.


Last edited by normhead; 04-14-2016 at 01:01 PM.
04-14-2016, 12:33 PM   #2
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I know the 1.4 works flawlessly (for me at least) with the 150-450, which gets you past 600. Now I want to give it a shot with the 1.7 in the middle.
04-14-2016, 12:33 PM   #3
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These are great Norm. TFS

I've been looking for a 1.4x or 1.7x to use with my Pentax 50-200 but haven't been able to locate either so far. I really like your results from stacking two TCs together.
04-14-2016, 12:33 PM   #4
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But wait, everyone knows that TC's degrade the image quality and make for poor images. And everyone knows you cannot stack two TC's...........

How can you post images and disrupt conventional 'wisdom' like that?

More seriously, what are you using for a tripod? I would think vibrations of any kind would be the real problem at that focal length. Whatever, you did good.

04-14-2016, 12:45 PM   #5
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QuoteOriginally posted by jatrax Quote
But wait, everyone knows that TC's degrade the image quality and make for poor images. And everyone knows you cannot stack two TC's...........

How can you post images and disrupt conventional 'wisdom' like that?

More seriously, what are you using for a tripod? I would think vibrations of any kind would be the real problem at that focal length. Whatever, you did good.
I have an old Blacks tripod out in the blind, that is basically out there because I'd be embarrassed to be seen by real photographers with it.
The usual caveats about needing extra care with a longer lens apply.
04-14-2016, 12:49 PM   #6
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QuoteOriginally posted by normhead Quote
K-3 and stacks HD DA 1.4TC and F1.7 AF adapter.

250 x1.4x1.7 gives me pretty much 600mm

One last reach experiment... after getting pretty much stellar results with the DA*200 2.8 and stacked TCs I decided to test my reach options. The A-400 and 1.7 which would give me 680, was a pretty dismal failure. I had trouble locking focus (and I had great light) and the best images weren't good enough. So after completing that, I realized I hadn't tried stacking with the DA* 60-250. So back out again.

I got far fewer keepers and often had considerable trouble locking focus, as much as with the A-400, the difference being, when I did lok focus the images were good.







So from my perspective, this becomes the poor man's way to get to 600mm 6.7. Really, not to shabby.

I guess I could point out that some have sold their Pentax gear and bought whole new systems to get to 600. And with full AF I'm sure those systems are more functional, but if you're on a budget and you own a DA* 60-250, this could be for you. I'd love to be able to try it out with a DA*300, also an 4 lens. I would expect similar results, similar trials getting images and similar joy with the results when successful.

714mm and 6.7 would not be too shabby, with this kind of IQ.
That is amazing, Norm !
If you don't mind me asking: what is the order in which the TC's are stacked? Or does it matter?
I have the DA*300/4 and both of those TC's, so it could be fun to try that!

Thanks!
04-14-2016, 12:49 PM   #7
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QuoteOriginally posted by photolady95 Quote
These are great Norm. TFS

I've been looking for a 1.4x or 1.7x to use with my Pentax 50-200 but haven't been able to locate either so far. I really like your results from stacking two TCs together.
Wo there, I'm not recommending stacking with anything less than an ƒ2.8 lens. Using the stacked TCs on the ƒ4 lens was dicey. With the 50-200 at ƒ5.6, everything I've done suggests you can't even use the 1.7 TC by itself. You could try the 1.4, but I wouldn't recommend it. By far the most functional stack I've used was the DA*200 and stacked TCs, I've used the DA*60-250 and would try it in a crunch, but it didn't give me the kind of reliable AF the DA*200 ƒ2.8 did.

It's unfortunate but you really do have to have the best glass to use stacked TCs.

QuoteOriginally posted by jpzk Quote
That is amazing, Norm !
If you don't mind me asking: what is the order in which the TC's are stacked?
Or does it matter?
Thanks!
I don't know if the order matters. I've always put the 1.4 on the camera and the 1.7 in the middle. That's what made sense to me. With the 1.4 turning the 1.7, both TCs are working for you. If you put the 1.7 on first, the 1.4 will be stationary, at whatever it's set to. But, who knows, maybe it would work equally well either way.

Last edited by normhead; 04-14-2016 at 12:58 PM.
04-14-2016, 12:54 PM   #8
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QuoteOriginally posted by normhead Quote
Wo there, I'm not recommending stacking with anything less than an 2.8 lens. Using the stacked TCs on the 4 lens was dicey. With the 50-200 at 5.6, everything I've done suggest you can't even use the 1.7 TC by itself. You could try the 1.4, but I wouldn't recommend it. By far the most functional stack I've used was the DA*200 and stacked TCs, I've used the DA*60-250 and would try it in a crunch, but it didn't give me the kind of reliable AF the DA*200 2.8 did.

---------- Post added 04-14-16 at 03:52 PM ----------



I don't know if the order matters. I've always put the 1.4 on the camera and the 1.7 in the middle. That's what made sense to me. With the 1.4 turning the 1.7, both TCs are working for you. If you put the 1.7 on first, the 1.4 will be stationary, at whatever it's set to. But, who knows, maybe it would work equally well either way.
Great.
Now, let's wait for birds .... still pretty scarce around here. Seems like Spring has decided not to sprung.

04-14-2016, 12:54 PM   #9
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QuoteOriginally posted by normhead Quote
but it didn't give me the kind of reliable AF the DA*200 ƒ2.8 did.
Auto focus smokous. Who cares about AF, the fact that you got what I would think are printable images with that rig is amazing. Very good technique I'm sure and good light but still, well done.

I assume the 60-250 was at f/4?

Have you tried the A-400 and the 1.4x? Curious if the IQ was fine though no AF of course.
04-14-2016, 01:00 PM   #10
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Whoa! I said and/or, not both. I have no intention of stacking two on a 50-200mm lens at it's f stops. But I have a Vivitar 2x and it will not allow autofocus to happen because the lens at 200mm is f5.6 and it needs to be less than f4 for a 2x TC to work.
04-14-2016, 01:06 PM   #11
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QuoteOriginally posted by normhead Quote
Wo there, I'm not recommending stacking with anything less than an 2.8 lens. Using the stacked TCs on the 4 lens was dicey. With the 50-200 at 5.6, everything I've done suggests you can't even use the 1.7 TC by itself. You could try the 1.4, but I wouldn't recommend it. By far the most functional stack I've used was the DA*200 and stacked TCs, I've used the DA*60-250 and would try it in a crunch, but it didn't give me the kind of reliable AF the DA*200 2.8 did.

It's unfortunate but you really do have to have the best glass to use stacked TCs.



I don't know if the order matters. I've always put the 1.4 on the camera and the 1.7 in the middle. That's what made sense to me. With the 1.4 turning the 1.7, both TCs are working for you. If you put the 1.7 on first, the 1.4 will be stationary, at whatever it's set to. But, who knows, maybe it would work equally well either way.

I'm confused. The 1.4 is always stationary. It only passes AF power or screw drive shaft power. Putting the 1.7 anywhere as long as AF shaft powers it gives focusing options. I always added it to the camera first. But typically my stacks involved non-AF Teleconverters. So an FA* 300 with 2x-s and then the AF 1.7x. My rationale was that the AF 1.7 would have the most focusing impact placed last in the optical path.
04-14-2016, 01:15 PM - 1 Like   #12
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QuoteOriginally posted by jatrax Quote
Auto focus smokous. Who cares about AF, the fact that you got what I would think are printable images with that rig is amazing. Very good technique I'm sure and good light but still, well done.

I assume the 60-250 was at f/4?

Have you tried the A-400 and the 1.4x? Curious if the IQ was fine though no AF of course.
My ƒ-stop showed the correct ƒ stop wide open a ƒ6.7, I stopped down to the next full ƒ-stop, ƒ8 just to be neat and tidy I guess. Oops my mistake. The 1.7 on a ƒ5.6 lens is ƒ9.5 so I actually stopped down to ƒ11.

QuoteOriginally posted by photolady95 Quote
Whoa! I said and/or, not both. I have no intention of stacking two on a 50-200mm lens at it's f stops. But I have a Vivitar 2x and it will not allow autofocus to happen because the lens at 200mm is f5.6 and it needs to be less than f4 for a 2x TC to work.
Thanks for spelling whoa, I was wondering how to spell it. My experience says the 1.4 might work on your 200, but probably not well and for the cost of the Pentax TC you could get a 55-300, that would be faster and more convenient.

QuoteOriginally posted by UncleVanya Quote
I'm confused. The 1.4 is always stationary. It only passes AF power or screw drive shaft power. Putting the 1.7 anywhere as long as AF shaft powers it gives focusing options. I always added it to the camera first. But typically my stacks involved non-AF Teleconverters. So an FA* 300 with 2x-s and then the AF 1.7x. My rationale was that the AF 1.7 would have the most focusing impact placed last in the optical path.
That's what happens when you think about things you shouldn't.

You've obviously thought about it a lot more than I have. My thought involved standing in front of the lens and two TC-s lying on the table in my kitchen, wondering which one to put first, staring at the three pieces.

Then when it worked, I saw no point in thinking any further.

You can't get away with nothing around here.

I bought the 1.7 before the 1.4, and it was my first TC. In my mind apparently, all TCs move, whether they claim to be AF adapters or not.

Oh and credit where credit is due, the original idea to try this stuff came from watching my Canon shooting buddies. I know I should probably not say stuff like that but hey.

We were standing around at the place we shoot Gray Jays, me with my old A-400 and one of the guys waved his Canon 70-200 ƒ2.8 with a Canon 2x on it and said, "I've got the same thing with AF and better IQ." The better IQ thing was against forum ideology, but, it's always better to investigate than it is to repeat hearsay. I managed to keep my foot out of my mouth. The thing that took the most time was getting to stacking the 2 TCs. Again, forum wisdom said "don't do that,". I went for quite a while thinking "it's too bad Pentax doesn't make 2x TC, before I even thought of stacking.

I guess the thing I took from the whole experience, is if you pay the price for premium equipment, don't take advice from people who didn't. The 1.7 and 1.4 are both premium pieces of equipment, and work best with premium glass. Any shortcuts are likely to mess up the whole process. Three combined pieces are only as strong as the weakest link.

Last edited by normhead; 04-14-2016 at 05:11 PM.
04-14-2016, 02:51 PM   #13
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Great results!

Wouldn't that be f/9.5 fully open instead of f/6.7?
f/4 - 1.5 stop (for the 1.7x) = f/6.7
f/6.7 - 1 stop (for the 1.4x) = f/9.5
04-14-2016, 03:42 PM   #14
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My suggestion is to try it again with the 1.7x closest to the body and see if the results are better. But before you do verify that the glass in the 1.7x won't contact the 1.4x - I did it and I think it works but then again I was a stupid person and mounted a DA 15 to the silly 1.4x once only without damage but found out later it was possible to damage one or both due to the way the glass protrudes.
04-14-2016, 03:56 PM   #15
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QuoteOriginally posted by VoiceOfReason Quote
I know the 1.4 works flawlessly (for me at least) with the 150-450, which gets you past 600. Now I want to give it a shot with the 1.7 in the middle.
That's good to know! Bet the 1.4 would work on full frame just fine with that lens as well... might be fun.
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