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02-15-2011, 06:59 PM   #31
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QuoteOriginally posted by Jodokast96 Quote
Lowell, for the record I'm not trying to argue with you or say you are wrong. But I will offer an opposing viewpoint and let Mel (or anyone else) figure out for themselves, that I have never seen this overexposure you claim exists when using a TC. No need to go posting your chart, because like I said, I'm not here to argue about it and am not going to take the time to post real world pics, etc. I just don't feel it's anywhere near the issue you make it out to be.
No chart no argument bit don't tell me and other K10/20 owners the issue does not exist. It has been measured. Also dOnt assume that a 1-1.3 stop over exposure is not an issue in the real world. It is

02-15-2011, 07:37 PM   #32
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Sure, a 1 stop over exposure is an issue, but don't tell me that it "constantly over exposes by 1.3 stops", because it is not true for everybody. You spread that around like it's the gospel, when the reality is, it's not. A K10/K20 + a TC does not automatically equal an issue. I can't use a split screen with my K10 and get correct flash exposure, and could measure it and make a chart showing the 4+ stop under exposure. But I don't tell everyone using a split screen it's a constant issue, because like myself with a TC, not everybody has that same experience. Instead of spreading it around and holding it up like the Holy Grail, I bring it to light to those that actually experience it as to what the cause may be.
02-16-2011, 04:44 AM   #33
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QuoteOriginally posted by Jodokast96 Quote
Sure, a 1 stop over exposure is an issue, but don't tell me that it "constantly over exposes by 1.3 stops", because it is not true for everybody. You spread that around like it's the gospel, when the reality is, it's not. A K10/K20 + a TC does not automatically equal an issue. I can't use a split screen with my K10 and get correct flash exposure, and could measure it and make a chart showing the 4+ stop under exposure. But I don't tell everyone using a split screen it's a constant issue, because like myself with a TC, not everybody has that same experience. Instead of spreading it around and holding it up like the Holy Grail, I bring it to light to those that actually experience it as to what the cause may be.
The specific point, and the discussion I have made in the past is based upon the performance of the K10D/K20D with the stock screen.

The +1-1.3 stops is with an F2.8 lens.

If you ever bothered to look at the chart I have posted in the past, and look how one of these cameras meters with a lens at F2.8 where no aperture data is present, and then look at how it meters at F4 or F5.6 with no aperture data available, then you will see how the error evolves. The K10D/20D tend to under expose by about a stop on manual lenses at F2.8. The camera when used with an F2.8 auto aperture lens adjusts for this because it KNOWS the wide open aperture, but adding a 2x TC without changing the data leaves the camera still thinking it has an F2.8 lens but in reality it has F5.6 so there is an error introduced.

This is the way the camera with stock screen works.

ANT teleconverter that simply feeds the aperture values through without modification will do this.

If you use a TC that modifys the aperture reading no you won't get this, but the only TC I know of personally is the SMC-F 1.7x AF Converter. It corrects for aperture. Perhaps some of the tamron and kenko TCs for the PZ1 are the same, I don;t know, I don't have them..

As for gospel, perhaps it is not but it should be. Cameras are mass produced devices under high quality standards, I do not believe myself and the others have special modesl which behave differently. All the cameras meter the same.

As for spreading the word. WHY NOT this is supposed to be a forum where we help others avoid issues, and some of that means posting what we have observed, so people can make decisions based upon the experience of others.

Would you prefer that I comment back, sure it works great, and then have people complain I didn't tell them about the exposure issue. That is not the purpose of the forum
02-16-2011, 03:15 PM   #34
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Well going back to the OS issue . . .
So far I'm liking the OS in the lens marginally better. But I haven't gotten anything to really display publically. I DEFINITELY need to practice with this behemoth some more.

02-16-2011, 06:15 PM   #35
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QuoteOriginally posted by mel Quote
Well going back to the OS issue . . .
So far I'm liking the OS in the lens marginally better. But I haven't gotten anything to really display publically. I DEFINITELY need to practice with this behemoth some more.
Re OS do you think it helps the AF by presenting a stable target? Do you use OS on a tripod?
02-16-2011, 06:19 PM   #36
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QuoteOriginally posted by mel Quote
I don't have a TC but with just a few cursory snaps, chimping in camera, it seems that it overexposes with just the lens itself compared to what I am used to seeing using Pentax lenses. Or even my 70-200 (Sigma) for that matter. But again, this is just cursory. I have yet to have time to load the images into my computer to really look at them. They just look overly light unless I use the EV at minus about a full stop.
I think my 150-500 is a tad on the bright side, where the Pentax's are a bit on the dark side. Not enough for me to do any EVC, though.

Oh, I use SR (and monopod) rather than OS - so I don't forget to turn it on with other lenses :-)

Last edited by SpecialK; 02-17-2011 at 04:23 PM.
02-17-2011, 01:09 PM   #37
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QuoteOriginally posted by Lowell Goudge Quote
Re OS do you think it helps the AF by presenting a stable target? Do you use OS on a tripod?
You're supposed to turn the OS off when using a tripod, just like in the SR system. As for stable target, well, when I'm trying to shoot the thing at 400 or 500, nothing is stable. I can't even hold the thing stable enough to be sure that what the focus is locked on is what I want it locked on

As I said, I need to practice with it more. And start a weight-lifting regimen.
02-17-2011, 03:16 PM   #38
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QuoteOriginally posted by mel Quote
I can't even hold the thing stable enough to be sure that what the focus is locked on is what I want it locked on
Good luck Mel with this lens, I hope it does both sides of the pitch as you intend.

Don't want to alarm you, but............................................. as the match goes on with all big glass, the damn things just seem to get heavier and heavier.

A good monopod can be a good friend, until all that "Arnie" training kicks in.

02-17-2011, 05:13 PM   #39
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QuoteOriginally posted by mel Quote
You're supposed to turn the OS off when using a tripod, just like in the SR system. As for stable target, well, when I'm trying to shoot the thing at 400 or 500, nothing is stable. I can't even hold the thing stable enough to be sure that what the focus is locked on is what I want it locked on

As I said, I need to practice with it more. And start a weight-lifting regimen.
This may be a dumb question but what is the point of OS if you don't hand hold?
02-17-2011, 05:53 PM   #40
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QuoteOriginally posted by Lowell Goudge Quote
This may be a dumb question but what is the point of OS if you don't hand hold?
Not much, especially for me. I have such an un-steady hand that I pretty much have to use a tripod for anything over 100mm or so, even with SR or OS (and of course, these are turned off when on a 'pod) if I expect the results to be really sharp. That's one reason I'm with Pentax. The SR at least allows me to go 'pod-less when I'm under 100mm.
02-17-2011, 07:14 PM   #41
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QuoteOriginally posted by Lowell Goudge Quote
This may be a dumb question but what is the point of OS if you don't hand hold?
OS has a 2-position switch, one of which does not affect horizontal panning, so I guess you could use it on a pan-head for that.
02-18-2011, 03:26 AM   #42
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QuoteOriginally posted by Lowell Goudge Quote
This may be a dumb question but what is the point of OS if you don't hand hold?
Exactly. I said the same thing further up . . .
02-18-2011, 06:57 AM   #43
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QuoteOriginally posted by SpecialK Quote
OS has a 2-position switch, one of which does not affect horizontal panning, so I guess you could use it on a pan-head for that.
I don't think so, since you would still have vertical problems with the tripod stiffness and SR system.

I know some use SR with the gimble heads, but that is somewhat different, as those heads are not locked stiff, but used to provide neutral balance for big lenses (the support is through the center of mass of the camera plus lens, therefore you can let go and nothing moves)
02-18-2011, 07:11 AM   #44
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I've been a little confused myself with my 120-400mm and the 2nd OS position - it is intended to be used for blurred panning purposes, correct? i.e. it is stabilized so that if I pan with a slower shutter, the blurred pan lines will be straight (ideally at least).

I am appreciating the OS in the viewfinder with the 120-400 as well, but like Mel, find it is definitely a beast to wield and needs practise, whether at 4 or 5 lbs, haha.
02-18-2011, 07:37 PM   #45
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QuoteOriginally posted by pxpaulx Quote
I've been a little confused myself with my 120-400mm and the 2nd OS position - it is intended to be used for blurred panning purposes, correct? i.e. it is stabilized so that if I pan with a slower shutter, the blurred pan lines will be straight (ideally at least).

.
Your instructions are probably as vague and crappy as mine. They say "Mode 2 detects the vertical camera shake, and overcomes blurring. It is effective on subjects moving horizontal to the camera". They don't expressly say "while panning the camera", but you have to assume that, or what's the point?

They also say...it's "effective for hand-held use", and "please don't use it if the lens is mounted on a tripod", or for bulb exposures. It also functions after the exposure and so you should not unmount the lens unless it is turned it off.
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