RE: K2 shutter vibration question
That's one reason my astro cameras are KX's and one Yashica Electro-X. They all have mechanical MLU. Very important on short exposures like the moon and planets. For longer ones you can just hold a black sheet over the telescope objective and wait a few seconds till all vibrations will have stopped and then pull it away to start the exposure. Kent Gittings -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Peter Spiro Sent: Thursday, October 25, 2001 11:26 PM To: [EMAIL PROTECTED] Subject: RE: K2 shutter vibration question Various tests have found that small differences in camera vibration can make big differences in resolution at moderately slow shutter speeds. People on the Olympus list have tested their cameras with or without diaphragm pre-fire, and it turns out that even the vibrations from the diaphragm closing down makes a substantial difference to resolution. This is apparently not something you can solve by locking the camera down, no matter how rigid the tripod. It seems to occur not because the camera moves, but because its body vibrates. I suspect that it has to something to do with the fact that the metal in cameras is mainly brass (the same metal used in musical instruments because it vibrates so well). When Keppler did a test (POP, June 99) of cameras with and without the mirror locked up, the biggest difference was around 1/15th of a second, where locking up the mirror could increase the resolution from a 135 mm lens by 80%. If you use a long exposure, like a few seconds, it won't make that much difference, since the vibrations will occur only for a small percentage of the time the exposure is underway. With a 5 second exposure, Keppler found that there was no difference in resolution with or without the mirror locked up. This might be why Mark Roberts likes his K2 with small apertures, long shutter speeds. When Popular Photography tested the K2 (December 1976) they reported the shutter vibration was about 0.7 volts, double the average of cameras tested up to that time. (For the cloth focal plane shutter MX, by contrast, the vibration level was about 0.2 volts). An easy subjective test you can do at home goes as follows: Set a small shot glass with about half an inch of water in it on top of the flash shoe, fire the shutter and watch for the ripples. You will find that you get much bigger ripples from a K2 (mirror locked up) than an MX or ME (mirror not locked up). As somebody suggested, it is possible that the K2's vibrations are mainly when the second curtain of the shutter hits the far end, in which case it won't cause much of a problem. Anybody who has a K2 can test for this quite easily.Lock up the mirror, set the shutter speed to B, and release the shutter with a cable release, holding it open. Watch for ripples in the water. If the camera is good, the ripples should be minimal. Then let the shutter close, and see if most of the ripple action is concentrated at that end of the cycle. I hope somebody tries this, and reports back to the group, to clarify this issue. I will be happy to revise my opinion of what is in many ways a fine camera. (I just did this test with my MX, at 1 second exposure, with the mirror locked up. Vibrations when the shutter opened were almost non-existent. BTW, on my MX the quasi-MLU does not seem to work at B.) _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org . ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Shutter Vibration Tested (RE: K2 shutter vibration question)
The following is from Peter: Date: Fri, 26 Oct 2001 03:25:33 + From: Peter Spiro [EMAIL PROTECTED] Subject: RE: K2 shutter vibration question Anybody who has a K2 can test for this quite easily.Lock up the mirror, set the shutter speed to B, and release the shutter with a cable release, holding it open. Watch for ripples in the water. If the camera is good, the ripples should be minimal. Then let the shutter close, and see if most of the ripple action is concentrated at that end of the cycle. I hope somebody tries this, and reports back to the group, to clarify this issue. I will be happy to revise my opinion of what is in many ways a fine camera. (I just did this test with my MX, at 1 second exposure, with the mirror locked up. Vibrations when the shutter opened were almost non-existent. BTW, on my MX the quasi-MLU does not seem to work at B.) Hi Peter et. al.: Okay, Peter, I tried the water test with the following cameras: SPII K1000 MeSuper LX K2 I did this with much trepidation as I had a bad experience Wednesday with water and camera combination (I dropped my Super Program in creek! Yikes, what a feeling!) I put each camera on a wooden cutting board and put a wash rag under the lens to cushion it a bit. I balanced a coffee mug 2/3 full of water and fired the shutter in B and watched for ripples. I re-ran all the cameras several times, checking again and again and finally checking the cameras in order of ranking. In general, the initial slap of the shutter was much less than the return. I would say roughly 50% less. Suprising to me was that the mirror lock up did make more difference than it did. The following would be my SUBJECTIVE ranking of initial vibrations-- Top 2 were close but 1. k1000 (very short waves, low amplitude) 2. LX - mirror up (similar to k1000, longer waves) Another close grouping 3. SPII (slightly longer waves than No. 2) 4. LX - mirror down (very similar to the SPII, slight more amplitude) Much worse than above 5. K2 - mirror up (long wave, a bit more amplitude than No. 4) 6. K2 - mirror down (a bit longer wave and amplitude than No. 5) 7. MeSuper - (longest wave, amplitude) The return curtain vibrations rankings were similar, maybe less difference between the LX, SPII grouping and the K2 MeSuper grouping. And I love that MeSuper! Ah well. As far as the K2 is concerned, I am sad to report that the initial slap, while less then the return curtain vibration, was still substantial, in my less than expert opinion. I hope someone else tries this as I do not want to be the final word on this subject. dave _ Get your FREE download of MSN Explorer ___ Send a cool gift with your E-Card http://www.bluemountain.com/giftcenter/ - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: K2 shutter vibration question
Robert Soames Wetmore writes: I've always admired the K2 as the ultimate of the Pentax K's. It has a feeling of solidity and a weight that bothers some but pleases me. I like the K2 as well. I have two of them which I use alongside my Z-1p. Solid, well-built and reliable, provided they're not stored on a shelf for 20 years... :) Like the KX, it has DOF preview and MLU, but in some other respects is specified even better. For its time it is a fine manual camera - and quite useful today. I would be inclined to believe it was Pentax's flagship of the day. It was the first bayonet-mount camera they commercially released (the KM, KX and K1000 followed soon after). I just love the viewfinder and the meter. And the 8-second shutter speed :) However, I keep hearing that its (Seiko-sha?) metal focal plane shutter induces a fair amount of vibration [see typical excerpt below]; this would sort of defeat the whole idea of MLU (which is the main reason I am thinking of investing in some K2's, to be used with larger glass, as upgrades of my K1000's, which I will keep for more portable photography). Can anyone confirm that this is true? Is there noticeable degradation of image clarity - and under what conditions? The shutter sounds pretty heavy but I haven't noticed any problems in my images because of it. I don't do a lot of work with long lenses and slow shutter speeds, but I do use the body for macro work quite often. I do use a sturdy tripod and use the mirror lockup whenever I can. In addition to its weight, it has two significant drawbacks: its ASA setting must be the most difficult of any camera ever made, Its not difficult, just different :) Once you know how it works its pretty easy to set. Until the dial stiffens up, then you get chewed-up fingernails. One of the little gotchas with this body is that you can't adjust the film speed unless the exposure compensation is set to zero. and its first-generation electronic shutter is noisy and vibration prone. The camera gives a kick that is not solved by locking up its mirror (a feature it has), which no doubt degrades image quality at slow shutter speeds. The wording implies to me that whoever wrote it has never actually tested it. He could be right, but as I indicated earlier I haven't noticed any problems, even at the horrible shutter speeds of 1/4 to 1/15 at 1:1 macro extension. I get more problems with subject movement due to wind. Cheers, - Dave David A. Mann, B.E. (Elec) http://www.digistar.com/~dmann/ Why is it that if an adult behaves like a child they lock him up, while children are allowed to run free on the streets? -- Garfield - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: K2 shutter vibration question
*** However, I keep hearing that its (Seiko-sha?) metal focal plane shutter induces a fair amount of vibration [see typical excerpt below]; this would sort of defeat the whole idea of MLU (which is the main reason I am thinking *** Yes, the vibration of the shutter is very strong. It can be even felt when handholding the camera. I got the K2DMD just for the MLU, which is lacking in almost anz other body except KX and LX. However, the K2 has more sources of vibrations... it§s not a body I would pick for its vibration-free operation now, I would use a KX or LX. But I dont have LX or KX, so I have to use mz K2DMD. Sources of vibration: Mirror. MLU solves this only PARTIALLY! The mechanism used for springing mirror up before exposure IS NOT COMPLETELY TURNED OFF when MLU is used!!! So it justs springs in vain, but inducing serious vibration nevertheless. Its better than without MLU, though. IMHO, this vibration of this source is STRONGER when the MLU is used!!! But as the mirror itself induces even more vibration, it§s still better to use MLU than not. Aperture. The aperture activating lever IS NOT TURNED OFF WHEN MLU is used. Another strong source of vibration. Holding in the DOF preview button makes it even worse, so it cannot be solved. Shutter. Even the shutter makes slight vibration, but in effect, it§s the smallest of those other sources. I can see the effects of these vibrations when I put the camera on tripod and put a glass with water on the camera, then use selftimer to trigger the shutter. Even with MLU, there are waves apparent on the surface of water. And I can see it in pictures, especially with long lenses. So fo extra long lenses, big wooden tripod is necessity. Frantisek - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
RE: K2 shutter vibration question
Various tests have found that small differences in camera vibration can make big differences in resolution at moderately slow shutter speeds. People on the Olympus list have tested their cameras with or without diaphragm pre-fire, and it turns out that even the vibrations from the diaphragm closing down makes a substantial difference to resolution. This is apparently not something you can solve by locking the camera down, no matter how rigid the tripod. It seems to occur not because the camera moves, but because its body vibrates. I suspect that it has to something to do with the fact that the metal in cameras is mainly brass (the same metal used in musical instruments because it vibrates so well). When Keppler did a test (POP, June 99) of cameras with and without the mirror locked up, the biggest difference was around 1/15th of a second, where locking up the mirror could increase the resolution from a 135 mm lens by 80%. If you use a long exposure, like a few seconds, it won't make that much difference, since the vibrations will occur only for a small percentage of the time the exposure is underway. With a 5 second exposure, Keppler found that there was no difference in resolution with or without the mirror locked up. This might be why Mark Roberts likes his K2 with small apertures, long shutter speeds. When Popular Photography tested the K2 (December 1976) they reported the shutter vibration was about 0.7 volts, double the average of cameras tested up to that time. (For the cloth focal plane shutter MX, by contrast, the vibration level was about 0.2 volts). An easy subjective test you can do at home goes as follows: Set a small shot glass with about half an inch of water in it on top of the flash shoe, fire the shutter and watch for the ripples. You will find that you get much bigger ripples from a K2 (mirror locked up) than an MX or ME (mirror not locked up). As somebody suggested, it is possible that the K2's vibrations are mainly when the second curtain of the shutter hits the far end, in which case it won't cause much of a problem. Anybody who has a K2 can test for this quite easily.Lock up the mirror, set the shutter speed to B, and release the shutter with a cable release, holding it open. Watch for ripples in the water. If the camera is good, the ripples should be minimal. Then let the shutter close, and see if most of the ripple action is concentrated at that end of the cycle. I hope somebody tries this, and reports back to the group, to clarify this issue. I will be happy to revise my opinion of what is in many ways a fine camera. (I just did this test with my MX, at 1 second exposure, with the mirror locked up. Vibrations when the shutter opened were almost non-existent. BTW, on my MX the quasi-MLU does not seem to work at B.) _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
K2 shutter vibration question
I've always admired the K2 as the ultimate of the Pentax K's. It has a feeling of solidity and a weight that bothers some but pleases me. Like the KX, it has DOF preview and MLU, but in some other respects is specified even better. For its time it is a fine manual camera - and quite useful today. However, I keep hearing that its (Seiko-sha?) metal focal plane shutter induces a fair amount of vibration [see typical excerpt below]; this would sort of defeat the whole idea of MLU (which is the main reason I am thinking of investing in some K2's, to be used with larger glass, as upgrades of my K1000's, which I will keep for more portable photography). Can anyone confirm that this is true? Is there noticeable degradation of image clarity - and under what conditions? From http://ca.geocities.com/spirope/PentaxSLR.htm; : In addition to its weight, it has two significant drawbacks: its ASA setting must be the most difficult of any camera ever made, and its first-generation electronic shutter is noisy and vibration prone. The camera gives a kick that is not solved by locking up its mirror (a feature it has), which no doubt degrades image quality at slow shutter speeds. Thanks, Rob _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: K2 shutter vibration question
Hi, On 24 Oct 2001 at 10:29, Robert Soames Wetmore wrote: I've always admired the K2 as the ultimate of the Pentax K's. It is. However, I keep hearing that its (Seiko-sha?) metal focal plane shutter induces a fair amount of vibration (...) Can anyone confirm that this is true? Is there noticeable degradation of image clarity - and under what conditions? With my M4/100 macro and Soligor 4.5/300 macro and some wides, nothing special. You can easily feel the heavy vibration, but as far as I can tell, the most of it happens when the shutter closes, so it shakes the camera after the exposure. From http://ca.geocities.com/spirope/PentaxSLR.htm; : In addition to its weight, it has two significant drawbacks: its ASA setting must be the most difficult of any camera ever made, IMO the ISO setting isn't bad at all. The exposure compensation is another thing: full stops only, too easy to move without notice. and its first-generation electronic shutter is noisy and vibration prone. The camera gives a kick that is not solved by locking up its mirror (a feature it has), which no doubt degrades image quality at slow shutter speeds. Modern shutters are better at this, no doubt. Use MLU, a good tripod, and try to avoid speeds between 1/4 and 1/15... I like my K2 a lot! Gabor - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: K2 shutter vibration question
I think the part about shutter vibration is complete bullsh*t. Perhaps the metal shutter vibrates a *little* more than the cloth shutter of the other K cameras. But enough to negate the benefits of locking up the mirror??? Hogwash. [...] Between its mass and mirror lock-up it produces *very* sharp images (given a good lens, of course). Mark Roberts This is excellent news - thank you for your opinion, Mark. This was my first thought too: that the camera's mass and MLU would lend it to excellent sharpness (assuming stability, lens quality, etc.). Also, though I've repeatedly heard of these shutter vibration rumors, I have seen no proof in a picture. A lot depends on when these vibrations happen with regard to the exposure - as Sas Gabor mentions below, it may be after the shutter is already closed. You can easily feel the heavy vibration, but as far as I can tell, the most of it happens when the shutter closes, so it shakes the camera after the exposure. [...] I like my K2 a lot! Sas Gabor Good to know! Thank you for your opinion as well. I think we also should include the vibration because our heart beats when the camera is hand holded and... Alexandre Suaide I'm not sure if you meant this as a joke, but I actually have this very problem. It is a major factor in shooting hand-held. Particularly if I hold my breath and if I'm using a moderate telephoto, I can feel and see the rhythmic (sometime a-rhythmic) movement of my heart very clearly. I do not know whether this is related to my minor heart condition - it's not exactly Marfin's syndrome, which would make hand-held shooting impossible, but the slightly uneven heart pulse may be enough to cause shaking in the limbs which is barely perceptible except in making hand held shooting more difficult. In fact, something like 20% (not sure of the exact number) walk around with a similar heart condition without being aware of it - it is not generally life-threating. I'm not trying to plead a special case here or illicit sympathy (and I wasn't the least bit upset by your comment) but, even for those with perfect hearts, the steadiness of the hands is greatly influenced by the heart - once proper breathing is learned, the heart beat is the limiting factor of steadiness in hand-held photography. Rob _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: K2 shutter vibration question
Robert Soames Wetmore wrote: I think we also should include the vibration because our heart beats when the camera is hand holded and... Alexandre Suaide I'm not sure if you meant this as a joke, but I actually have this very problem. It is a major factor in shooting hand-held. Particularly if I hold my breath and if I'm using a moderate telephoto, I can feel and see the It depends on the situation. For some people it really makes difference. Using long lens sometimes we can notice that. But, anyway, there are so many factors in Nature that could make the camera vibrates that is impossible to eliminate all of them. The main point is we should learn to live with them. Even the better camera in the world with bet better tripod is not vibration free. Alex -- --- Alexandre A. P. Suaide, PhD mailto:[EMAIL PROTECTED] STAR/EMC group Phone: (WSU) (313) 577-5419 Wayne State University (BNL) (631) 344-7635 --- - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
