165mm LS Clarification

[steve_rasmussen]

I know that the 90LS and 165 LS lenses are different and that the 90mm has a "U" and "S" option. One mode for flash and the other for special applications. I don't own either lens but was wondering if it is possible for the 165 to reduce shutter shake by setting the focal plane shutter to 1 sec and setting the lens to 1/125 or so? I had always thought this was possible. I would like responses from owners of the 165LS. SR

[milton_barrocas]

"One mode for flash and the other for special applications"

 

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This is not totally correct. Both modes have the same flash

capabilities. The real difference is that the 90LS allows the leaf

shutter to be tripped any time after tripping the camera's shutter or

locking the mirror. This means that camera shutter vibration and

mirror up vibration can be totally eliminated with the lens in the 'S'

mode. It makes sense to use this mode in almost all tripod restricted

shooting. If you dont believe me check the lens manual. Pentax flat

out claims that "vibration reduction" is one of the advantages for

this lens.

As far as slow shutter speed, it is indeed possible to do what you say

but this will not help you in terms of vibration. Remember that the

leaf shutter fires almost immediately after the auto-aperture lever is

activated (on the P67 this happens as soon as the mirror flips up and

this is the reason the lens does not support mirror lock when using

the leaf shutter). On the 160 LS as soon as you bring the mirror up

the leaf shutter fires even if the camera shutter is not tripped yet

(on the P67 auto-aperture lever will activate when either the camera's

shutter is tripped or the mirror is locked). What this really means is

that mirror lock is not possible at all with this lens (in leaf

shutter mode) and hence you get the full mirror vibration effects when

the leaf shutter is tripped (so the camera's shutter vibration really

becomes irrelevant since the mirror vibration, as I'm sure we all

agree, dominates). Setting a slow shutter speed on the camera does

nothing to improve mirror vibration. Its a shame Pentax decided to

neglect the functionality of the 90LS (I use the 90LS in the S setting

probably 85% of the time, and this is probably why I think the images

from this lens are so spectacular and make this lens very valuable). I

believe they reasoned (for cost savings) that users of the 160 LS use

the lens for handheld portraiture using high shutter speed and hence

mirror lock is not practical and vibrations are not as much an issue

due to the high shutter speeds and flash freeze. I also beleive they

reasoned wrong since I only use my 160LS that way maybe 5% of the time

so I think the lack of the independent leaf shutter trip severely

limits the usefulness of the leaf shutter in this lens. Remember there

was a reason Pentax (and other manufacturers) went to the trouble of

adding an extra switch and cable release to their leaf shutter lenses.

Once you start using these lenses you soon realize its importance. And

how much could a simple switch and cable release socket add to the

price of the lens? On the 90LS, to me, they are worth 10X their weight

in gold, no...no, make that platinum. Coming to think of it Pentax

should take the old 90LS tooling modify it to increase the focal

length to 100mm and sell this lens as the "normal" lens and scrap the

105mm. This would ensure that every single P67 buyer would buy the

"normal" lens and put it to maximum use and further increase the

bang-for-the-buck the P67 system delivers.

[steve_rasmussen]

Milton, you have given some good information here. I didn't realize

Pentax had screwed up so badly on the 165 LS vs the 90 Takumar. I

don't agree that the mirror dominates in the vibration department with

this camera however. In my handheld work, I have had softness of

images due to the shutter more than the mirror. This was proven out

when I noticed that the left side of some slides were soft and not the

middle or right side. This is a shutter induced anomaly. Vertical

handheld shots with my 150 Takumar at 1/30 sec have mostly been tack

sharp. Horizonals are not quite as good, but it is known that shutter

shake is reduced when shooting vertical with this camera. My point

is, that the 165LS should do OK even though the leaf shutter is

activated right after the mirror moves up. The mirror shake should not

be a big issue. Have you tried shooting with the focal plane at long

exposures and the LS at short speeds with the 165LS handheld? How

about the same situation on the tripod? What were the results?

[milton_barrocas]

For me using the leaf shutter handheld without mirror lockup has never

provided any measurable improvement over using the camera's shutter

without mirror lockup. Again I believe that hand steadiness and mirror

vibration are the limiting factors when shooting handheld (I have a

hard enough time preventing the camera from turning when the mirror

flips up let alone vibration). I have never seen the 'left side'

softness gremlin with any of my lenses (I shoot about 500 rolls a year

and have a very fine enlarging lens and regularly enlarge to 20X24). I

also regularly attempt to use mirror lock when shooting handheld

(that's another peeve with the P67II, the MUP switch could not

possibly be any harder to activate handheld, why couldn't pentax just

add a push button next to the shutter release?).

For the love of me I cant disagree with you more regarding getting

more vibration from the shutter than the mirror. What vintage of

camera do you have? Perhaps I should mention that I own a P67II. But

results are results, for me the 90LS has consistently delivered the

sharpest pictures ever since I started using the 'S' mode and I would

not trade this lens for any other Pentax lens (well maybe the 800ED).

A lot of times I use the lens for landscapes at 1/30 sacrificing the

extra angle of view and DOF that I would get from my 55mm. The same

cannot be said about the 160LS. I've owned this lens for about 2 years

and regularly shoot with it but have never noticed any difference in

sharpness when using the leaf shutter whether on tripod or handheld.

Again I believe the leaf shutter produces less vibration than the

camera's shutter but since I cant lock the mirror when using the leaf

shutter I wind up shooting with the camera's shutter and ML whenever

possible. So in my opinion the only advantage of the leaf shutter is

the high flash sync which still makes this lens more valuable than the

160F2.8.