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03-01-2010, 08:18 PM   #31
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QuoteOriginally posted by jpzk Quote
Is this large lens still carry-able on a two-three hour trek?
Sure (but in that 2 or 3 hours you'll only get 75 yards down the trail.) The A*400mm is really not well suited to that sort of excursion. In addition to being too heavy, its physical configuration makes handling awkward--like a greased cannonball. It's hard to beat the DA*300 & 1.7x for trekking, imho.


Last edited by dadipentak; 03-02-2010 at 04:39 AM. Reason: elaboration
03-09-2010, 08:56 AM   #32
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QuoteOriginally posted by dadipentak Quote
Sure (but in that 2 or 3 hours you'll only get 75 yards down the trail.) The A*400mm is really not well suited to that sort of excursion. In addition to being too heavy, its physical configuration makes handling awkward--like a greased cannonball. It's hard to beat the DA*300 & 1.7x for trekking, imho.
75 yards, hey? That would be totally unacceptable considering that this is the distance I walk before I get to the trails from the parked car!
I have seen photos of this sort of lens but never held one in my hands. Looks like quite a chunk of glass but does it ever look good!

Sure enough that the combo 300/4 and a 1.7X TC is hard to beat on lengthy excursions.
The only down side to that is the resulting F6.7 max aperture; more often than not, the weather is not cooperating and that means upping the ISO quite a bit.

Oh, this is a question I have but not quite sure if that is acceptable on this thread .... here it goes anyway:

When using a 1.4X TC on a DA*300/4, either on the K20D or the K7, the camera indicates that I am still able to use F4 ... !? (shows on the small top screen) Shouldn't that be F5.6 instead?
Do I need to have my eyeglasses adjusted?

JP
03-09-2010, 10:09 AM   #33
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We now return from our impromptu threadjacking.

Um, back to SR and focal lengths. Let's go the other way. Not TC's -- macro tubes.

Let's say, perv that I am, that I put 50mm of extension onto a 50mm manual lens for some hot-and-heavy handheld 1:1 macro shooting. What do I tell the SR robot is my focal length? Is it different for an Industar-50 f/3.5, which is nearly a pancake, than for a SuperTak f/1.4, whose front element extends rather further? Mind you, I don't have the ST 50/1.4, but my ST 55/1.8 is about twice as thick as the Industar. How do we factor tube extension and lens thickness into focal length?

QuoteOriginally posted by jpzk Quote
When using a 1.4X TC on a DA*300/4, either on the K20D or the K7, the camera indicates that I am still able to use F4 ... !? (shows on the small top screen) Shouldn't that be F5.6 instead?
Do I need to have my eyeglasses adjusted?
Apparently the TC is unable to tell the camera just which lens is sitting on it. Poor stupid thing, that. And yes, you need new glasses. With rhinestones.

Last edited by RioRico; 03-09-2010 at 10:15 AM. Reason: answers
03-09-2010, 12:14 PM   #34
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QuoteOriginally posted by jpzk Quote
75 yards, hey? That would be totally unacceptable considering that this is the distance I walk before I get to the trails from the parked car!
I have seen photos of this sort of lens but never held one in my hands. Looks like quite a chunk of glass but does it ever look good!

Don't let Dave (dadi) mess with you. If you can carry 6 kg then you can carry the lens. But you won't catch me going on a hike with it. I'm thinking of using a garden cart.

Oh, this is a question I have but not quite sure if that is acceptable on this thread .... here it goes anyway:

When using a 1.4X TC on a DA*300/4, either on the K20D or the K7, the camera indicates that I am still able to use F4 ... !? (shows on the small top screen) Shouldn't that be F5.6 instead?
Do I need to have my eyeglasses adjusted?

JP
Of the 5 TCs I have, only the Pentax AF 1.7x actually show you the 1.5 stops hit in the aperture display. All the others have the 1-2 stop hit in light but just don't display it. I actually don't like the way the 1.7x does that since I have to mentally keep track of the apertures I want to use then subtract the 1.5 stops in order to set it.
With the other TCs I just use the aperture I want for speed or best sharpness at that distance then only worry about the shutter speed. Hope this ramble makes sense.

edit - Lets move any continuation of this discussion to the 300mm Lens Club thread.

03-10-2010, 01:19 PM   #35
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QuoteOriginally posted by RioRico Quote
Um, back to SR and focal lengths. Let's go the other way. Not TC's -- macro tubes.

Let's say, perv that I am, that I put 50mm of extension onto a 50mm manual lens for some hot-and-heavy handheld 1:1 macro shooting. What do I tell the SR robot is my focal length? Is it different for an Industar-50 f/3.5, which is nearly a pancake, than for a SuperTak f/1.4, whose front element extends rather further? Mind you, I don't have the ST 50/1.4, but my ST 55/1.8 is about twice as thick as the Industar. How do we factor tube extension and lens thickness into focal length?



Apparently the TC is unable to tell the camera just which lens is sitting on it. Poor stupid thing, that. And yes, you need new glasses. With rhinestones.
Rio:
I thought I started this thread about TC's, particularly the 1.7X Pentax AF-adapter ... but your question is about macro photography?
So, the TC is unable to tell the camera what lens is on? Of course, the camera is asking what lens you put on, in this case a 1.4X TC or, as per the purpose of this thread, a 1.7X TC.
My question was: why is the camera not requesting to input the focal length with a 1.4X Tamron TC while it does when using a 1.7X TC?

I am getting my glasses re-adjusted next week ... hopefully that will correct the false reading off the camera screen!

JP
03-10-2010, 01:22 PM   #36
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QuoteOriginally posted by imtheguy Quote
Of the 5 TCs I have, only the Pentax AF 1.7x actually show you the 1.5 stops hit in the aperture display. All the others have the 1-2 stop hit in light but just don't display it. I actually don't like the way the 1.7x does that since I have to mentally keep track of the apertures I want to use then subtract the 1.5 stops in order to set it.
With the other TCs I just use the aperture I want for speed or best sharpness at that distance then only worry about the shutter speed. Hope this ramble makes sense.

edit - Lets move any continuation of this discussion to the 300mm Lens Club thread.
How do we get to move this to the 300mm plus club?

So, when I put the 1.4X TC (Tamron) ... I don't need to input the focal length, so I assume the camera is set just right?
With the 1.7x adapter, just input the focal length and that is it, right?

OK, will be looking for the move of these posts.

JP
03-10-2010, 02:09 PM   #37
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QuoteOriginally posted by jpzk Quote

So, when I put the 1.4X TC (Tamron) ... I don't need to input the focal length, so I assume the camera is set just right?
With the 1.7x adapter, just input the focal length and that is it, right?


Hi Jacques,

With any pass through AF TC (everything except the 1.7x AFA) the camera will use the FL info from the lens without taking into account the TC's magnification. The FL shown in the exif is the SR system FL used for the shot. This is a known glitch with SR implementation.

For SR (and focus microcorrections), the camera has one memory slot for unrecognized lenses (lenses that don't have the chip that identifies the lens and contains FL info -- like the AFA and any MF lens). The camera will remember the last setting applied, regardless of the lens used.

Scott
03-13-2010, 08:58 AM   #38
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QuoteOriginally posted by snostorm Quote
Hi Jacques,

With any pass through AF TC (everything except the 1.7x AFA) the camera will use the FL info from the lens without taking into account the TC's magnification. The FL shown in the exif is the SR system FL used for the shot. This is a known glitch with SR implementation.

For SR (and focus microcorrections), the camera has one memory slot for unrecognized lenses (lenses that don't have the chip that identifies the lens and contains FL info -- like the AFA and any MF lens). The camera will remember the last setting applied, regardless of the lens used.

Scott
Hi Scott.
So what that means is that the camera will set the real lens focal length but in reality, we are shooting at 1.4X 300mm = 420mm. (for the Tamron 1.4x "normal" TC).
Wouldn't that cause some out of focus problems? I did some shooting with the DA*300 plus the 1.4X TC and that produced less "keepers" than I expected.

The 1.7X AF adapter use requires input of the focal length, in this case that would be 500mm (closest to the 510mm real total focal length).
As long as it is a fairly contrasty day - good light and contrasty subject - I find the results quite similar to using the 1.4X TC = less keepers again.
Some people use it differently:
they turn the camera SR off, turn the camera off, install the lens/1.7x AF adapter, turn the camera on, and at that point there is no "request" to input the focal length.
I tried that. I found that the shots were not as sharp as when I had to input the focal length "as per requested" by the camera.

Anyway, that is sometimes confusing as to what is the best method to use. I guess whatever works best is what one should use.

JP

03-13-2010, 07:38 PM   #39
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QuoteOriginally posted by jpzk Quote
Hi Scott.
So what that means is that the camera will set the real lens focal length but in reality, we are shooting at 1.4X 300mm = 420mm. (for the Tamron 1.4x "normal" TC).
Wouldn't that cause some out of focus problems? I did some shooting with the DA*300 plus the 1.4X TC and that produced less "keepers" than I expected.

The 1.7X AF adapter use requires input of the focal length, in this case that would be 500mm (closest to the 510mm real total focal length).
As long as it is a fairly contrasty day - good light and contrasty subject - I find the results quite similar to using the 1.4X TC = less keepers again.
Some people use it differently:
they turn the camera SR off, turn the camera off, install the lens/1.7x AF adapter, turn the camera on, and at that point there is no "request" to input the focal length.
I tried that. I found that the shots were not as sharp as when I had to input the focal length "as per requested" by the camera.

Anyway, that is sometimes confusing as to what is the best method to use. I guess whatever works best is what one should use.

JP
Hi Jacques,

What I do is to use the closest FL that I can for the SR. In the case of a 300 + 1.7x AFA, it would be 500mm. With the pass through AF TCs, you have no choice, and must use the unmagnified FL recognized by the camera body. Hopefully, you can compensate for the less effective SR by stepping up your long lens handholding technique. SR only augments long lens technique -- it does not replace it.

Lower percentage of keepers with a TC is usually dismissed to image degradation by the TC, but when good quality TCs are used with premium lenses this is, IMO, something of a bad rap (except maybe in the case of most 2x or greater TCs). Most users will try a few shots, and assume that the problem is the TC, but (again IMO) the problem is more likely a combination of testing procedure and technique. Another reason many have dismissed TCs is that they try them with less than optimal lenses, then assume that the TC is at fault when all it has done is magnify the limitations of the lens used. My usual comments on TCs apply only to use with premium lenses. . . but I digress. . .

Consider this -- most shooters, when "testing" a new TC, will take some shots with the bare lens, then install the TC and take their comparison shots at the same settings, using similar technique if handholding. This stacks the test against the TC from a number of standpoints. Handholding a 500mm lens is considerably more demanding of technique than using a 300mm, and while I seem to be able to shoot at 300mm pretty casually, I have to really concentrate on technique at 500mm. And then there's the light loss caused by the TC's magnification. To keep things kinda fair, you'd have to bump the ISO up an appropriate number of stops plus increase shutter speed by a factor equal to the TC magnification (as is indicated by the 1/FL "rule") -- even with SR -- Finally, you have to disregard any image degradation caused by increased noise at higher ISO -- it's really not that easy to do this test fairly. . .

A good alternative is to do the test indoors with flash to eliminate technique faults as much as possible. Try this, and I think you'll be impressed. The point is to determine the true image quality potential of the lens/TC combination, then knowing this, the challenge is to step up your technique to equal the gear's potential in real life situations.

Scott
03-15-2010, 11:58 AM   #40
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QuoteOriginally posted by snostorm Quote
Hi Jacques,
Thanks for the reply, Scott!
What I do is to use the closest FL that I can for the SR. In the case of a 300 + 1.7x AFA, it would be 500mm. With the pass through AF TCs, you have no choice, and must use the unmagnified FL recognized by the camera body. Hopefully, you can compensate for the less effective SR by stepping up your long lens handholding technique. SR only augments long lens technique -- it does not replace it.
That is what I did and of course, I could use more stability when shooting at 500mm (lens plus TC) but nearly 100% of the time, I don't use the tripod/monopod because of where I go. I will try to post some pics I took this weekend and that time I really could/should have use the tripod. However, the ball head is not quite what you would call "user friendly".
Lower percentage of keepers with a TC is usually dismissed to image degradation by the TC, but when good quality TCs are used with premium lenses this is, IMO, something of a bad rap (except maybe in the case of most 2x or greater TCs). Most users will try a few shots, and assume that the problem is the TC, but (again IMO) the problem is more likely a combination of testing procedure and technique. Another reason many have dismissed TCs is that they try them with less than optimal lenses, then assume that the TC is at fault when all it has done is magnify the limitations of the lens used. My usual comments on TCs apply only to use with premium lenses. . . but I digress. . .
True enough.
When I "test" a lens/TC combo, I just do it without first doing "lens only" tests. I know from experience that if you do the lens-only, then the lens/TC, and using the same parameters, chances are that you will end up rather disappointed with the results.
Your point of using good glass and a good TC is also obvious to me. I guess I have had too many bad shots in the past using, for instance, a DA 18-250 and a Tamron 1.4X TC.

Consider this -- most shooters, when "testing" a new TC, will take some shots with the bare lens, then install the TC and take their comparison shots at the same settings, using similar technique if handholding. This stacks the test against the TC from a number of standpoints. Handholding a 500mm lens is considerably more demanding of technique than using a 300mm, and while I seem to be able to shoot at 300mm pretty casually, I have to really concentrate on technique at 500mm. And then there's the light loss caused by the TC's magnification. To keep things kinda fair, you'd have to bump the ISO up an appropriate number of stops plus increase shutter speed by a factor equal to the TC magnification (as is indicated by the 1/FL "rule") -- even with SR -- Finally, you have to disregard any image degradation caused by increased noise at higher ISO -- it's really not that easy to do this test fairly. . .

A good alternative is to do the test indoors with flash to eliminate technique faults as much as possible. Try this, and I think you'll be impressed. The point is to determine the true image quality potential of the lens/TC combination, then knowing this, the challenge is to step up your technique to equal the gear's potential in real life situations.
Never occurred to me that this could be done for testing a lens/TC. Good idea and I will try it.
Scott
So, here are a couple of shots taken a few days ago: DA*300/4 and Pentax 1.7X AF-adapter; hand held. (I hope I'll be able to post them this time ... I always have a tough time with this.

2nd. photo: bird at approximately 25 meters away, on top of a tall tree. Couldn't just get her to look at me! Cropped about 25%.
1st. photo: bird at approximately 80+ meters away and flying low in a backlit situation. Cropped about 50%

Last edited by jpzk; 08-30-2015 at 06:48 PM.
03-15-2010, 08:10 PM   #41
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QuoteOriginally posted by jpzk Quote
So, here are a couple of shots taken a few days ago: DA*300/4 and Pentax 1.7X AF-adapter; hand held. (I hope I'll be able to post them this time ... I always have a tough time with this.

2nd. photo: bird at approximately 25 meters away, on top of a tall tree. Couldn't just get her to look at me! Cropped about 25%.
1st. photo: bird at approximately 80+ meters away and flying low in a backlit situation. Cropped about 50%
Hi Jacques,

WOW! Snowy Owls -- unfortunately for me, only a dream. . . Very nice work, even if you couldn't get her to pose!

Scott
03-15-2010, 08:22 PM   #42
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Yep...JP has access to some really interesting subjects. Fortunately he also knows how to shoot them. I have seen damn few decent shots of flying Snowy owls.

Good work Jacques!
03-17-2010, 07:46 AM   #43
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QuoteOriginally posted by snostorm Quote
Hi Jacques,

WOW! Snowy Owls -- unfortunately for me, only a dream. . . Very nice work, even if you couldn't get her to pose!

Scott
Thanks Scott!
Perhaps North of Lake Michigan? But that would be quite a ride for you to get there.
You know, I walked all around that tree for about half hour, very slowly and silently and she was just looking at me walking; as soon as I was ready to get the camera to my eyes, she'd just turned her head away!
I suppose she was just letting me know not to bother ... refusing to cooperate.
Lucky enough that she stayed there for that long though.
JP
03-17-2010, 07:55 AM   #44
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QuoteOriginally posted by imtheguy Quote
Yep...JP has access to some really interesting subjects. Fortunately he also knows how to shoot them. I have seen damn few decent shots of flying Snowy owls.

Good work Jacques!
Hi Lee; thanks for the comments.
When I think about it, if you're patient enough and have a good dose of weather resistance, you can usually stand/sit there and just wait.
Snowies are very much routine birds and most of the time will scan/hunt in the same areas, as long as there is enough food for them.
The area where I took these pics is obviously quite plentiful with small rodents.
Once you know their habits, it becomes much easier to predict what will happen and where you should be standing/sitting. I prefer trying to sit, of course. In the mud (which sometimes contains other not-to-be-mentioned organic materials) if need be!
As you know, I don't use the tripod during those shooting sessions; yes, I know I should, but my current tripod ball-head is not quite fluid enough for this sort of panning. The lens is small/light enough for hand-held pics (DA*300/4 plus a 1.7X TC).

JP
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