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paul_noble

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  1. I used to have a Pentax K-10d, which is pretty much identical to the GX-10. In addition to the things mentioned here, the camera has a dust removal feature that can be enabled. When it is enabled, it activates the SR (shake reduction is Pentax term for it) when the camera is powered on. The idea is to shake any dust off of the sensor. If you activate it and then turn the camera on, while holding it close to your ear, you should be able to hear the buzz of the sensor moving. IBIS, as implemented in Pentax cameras and their Samsung counterparts, has the advantage that it works with any lens you can mount on the camera. Pentax is very good about backward compatibility. The company claims that any Pentax lens, designed for their 35mm cameras, can be used on any Pentax dslr, and will benefit from SR. Canon and Nikon, with in-lens stabilization, can not make this claim. One drawback to IBIS is that, as pointed out, if does not show up in the optical viewfinder. I now have a Pentax K-5, which has live-view (the K10d, GX-10 do not), so I think I will experiment to see if I can see the difference in live-view.
  2. If the original poster is reading this, I suggest that she get a copy of "Understanding Exposure" by Bryan Peterson. In it, he explains the exposure triangle; shutter speed, aperture and film speed (sensitivity). He shows how, in theory, there are an infinite number of exposure combinations that will result in a "correct" exposure. But he also discusses the idea of artistic expression; what you intend to accomplish with your exposure. He then talks about how to choose which of the many "correct" exposures will create that effect. This includes using slow shutter speeds to show subject motion, as well as using different aperture settings to create various depth-of-field choices. In the digital age, we are lucky. Back in the film era, if I wanted to use a high shutter speed, such as 1/1000 second to freeze motion, along with a tiny aperture, such as f/16 to give me great depth of field, I might not be able to do because I was stuck with the film that was in the camera. I would have to make a choice between freezing motion or depth of field. Today, with my dslr, I can simply crank up the ISO setting to enable me to use that combination. BTW, extremely long exposures, several minutes in length, can effectively make people disappear. I have a welders mask lens epoxied to a Cokin filter holder. This lets me use exposures as long as five minutes at f/16 on a sunny day, with the camera mounted on a tripod. Any people in the picture, who are moving, will usually not sit still long enough to appear in the image, while the buildings and landscape will.
  3. It seems to me that scanner lines could be ruled in or out by re-scanning the negative in different orientations; rotate the negative 90 degrees between each scan. Perhaps scan on a different area of the scanner if that is possible. If the scanner is producing the lines, they should change with the different scans. If the lines remain the same orientation to the film, then the lines are actually in the negative.
  4. I, too, learned that trick, back in the day, when everything was on film. There was no digital. I don't think that it will work with that camera. Here is a link to an article I found about the Samsung Vega 140s. https://www.35mmc.com/08/06/2016/samsung-vega-140s-review/ It appears that there is no manual rewind crank, as you had on your Nikkormat and I had on my Pentax Spotmatic. It looks to be a high-end point and shoot camera from the late nineties. It looks like it has an automatic power rewind. It would be very difficult to avoid rewinding the film all the way back into the cartridge.
  5. That was not a bad, if necessarily brief, description of what an ISO rating is. Since he has already covered the creative use of shutter speed and aperture in previous articles, it would have been nice if he had at least made a comment about how different ISO settings affect shutter speed and aperture. If you're trying to take a portrait and you want very narrow depth of field, you want a lower ISO setting so that you can use a wider aperture. In answer to his question as to why one wouldn't simply always use the highest available ISO setting, all he mentioned was the increased noise at higher levels.
  6. Thanks for all your responses. It helps. I still haven't resolved my problem, but this discussion will help.
  7. I have an old Argus EF twin lens reflex from about 1947, that belonged to my dad. It uses 620 film which isn't available anymore. I bought a roll of Ilford Delta 400 black and white film in 120. I'm respooling it onto 620 spools. My problem is that, when I advance the film, I don't see any frame numbers. The camera has a little opening in the back, with a red filter and a spring-loaded shutter that you move out of the way while advancing the film. On 620 film (and 120 rolls I've used before) there were frame numbers printed on the backing paper. I rolled and rolled the film, but never saw any frame numbers. Does Ilford 120 not have frame numbers printed on the backing paper? I took the camera into a dark bathroom and opened the camera. The film had advanced over half the roll. I rerolled it back onto the feed spool and taped it so it wouldn't unravel. The camera store here, which is a pretty good one (they handle all the pro equipment here in Cleveland) only had Ilford b & w in single rolls. The had Kodak film but it was all in five-roll "bricks".
  8. Do the math (its easy). Pick a focal length. It really doesn't matter. Let's say 50mm. Calculate the area of the circle formed by the iris at f/1.4. A = ((50/1.412)/2)**2 * pi (the answer is 984 mm**2) Now calculate the area of the iris at f/2 A = ((50/2)/2)**2 * pi (the answer is 490 mm**2), or half the area of the circle at f/1.4. So, an aperture of f/2 admits exactly half the light per unit of time that an aperture of f/1.4 does. Conversely, f/1.4 admits twice the light that f/2 does. It is left as an exercise for the interested student to perform similar calculations for f/2.8, f/4, f/5.6, f/8 and so on. You will find that, at each step, the area is half (allowing for rounding) the area of the previous step.
  9. One nice feature that is present on (AFAIK) all Pentax dslrs is "catch in focus". I don't know if other manufacturers have this or not. With CIF, you can use a manual lens and, while the camera will not focus the lens, it will give a signal when you achieve proper focus. Years ago, Pentax made an autofocus lens extender. I believe it was 1.7x. The extender itself would move the entire lens forward and backward in response to the AF mechanism of the camera. This, effectively turned a manual focus lens into an autofocus one. It was, admittedly, a compromise, but it did work but with limitations. They still pop up on eBay occasionally, but they're a bit pricey. Pentax probably has the best backward compatibility of any brand. Any lens ever designed for a Pentax 35mm SLR can be used on any Pentax dslr. The screw mount lenses require an inexpensive adapter and require stop-down metering, but they will work. Any k-mount lens will fit and will work as the lens was designed.
  10. Technically, f/22 is really f/22.623 (sqrt(2)**9). Two stops is sqrt(2)**11, which is 45.2548.
  11. I agree. Analog refers to electronic technology. Audio tape is analog. The signal recorded on the tape varies as an analog of the pitch and amplitude of the original sound. a CD is digital audio. The original sound is sampled at a very high rate and reduced to a number. That number is etched as a binary number onto the substrate of the blank CD. Photographic film is a CHEMICAL process. So, the opposite of digital photography is not analog photography, but chemical photgraphy.
  12. paul_noble

    mystery lens

    If your lens (camera end) looks like the third photo posted, that is definitely the inner part of a T2 mount adapter. This part is the same for all cameras. The outer part of a T2 adapter mates to the particular camera you wish to use and had three small set screws that allow you to rotated the adapter, so that the markings for focus and aperture are always on top. The easiest thing to do is buy a complete T2 adapter, loosen the three set screws and discard the inner part of the new adapter. Place the outer part of the adapter over the part on the lens, adjust so the markings are where you want them to be, and tighten the set screws. Then forget about it and simply use the lens. A more complete fix would be to use a pipe wrench or an adjustable jaw pliers (commonly called "Channel Locks" here in the US). SInce the inner adapter on your lens is worthless, simply grip it with the pliers and hold the lens barrel with you other hand. That should get it off to expose the 42mm x 0.75 tpi thread. Then, but a complete adapter for the camera or cameras of you choice, screw it on the lens and fire away.
  13. It doesn't appear that anyone has asked what kind of slide film the OP found. It should be noted that, if it is Kodachrome, there is no place to have it processed as color images. It can be developed as B & W, but not color.
  14. That sounds like Seattle Film Works. They respooled 35mm movie film into cannisters for still cameras. They went belly-up in 2010. Seattle FilmWorks - Wikipedia
  15. I find it a bit ironic that we're talking about using 35mm movie film in our still cameras. That's how Ernst Lietz got started and built the first 35mm Leica camera. Full circle. I too lament the passing of Kodachrome. I don't think its coming back. The processing is too expensive, the market is too limited and there are probably environmental regulations that any new processing facility would have to overcome. For a long time, I firmly believed that, as the flagship product, Kodachrome would be the last film that Kodak made. I was wrong. I still have several film cameras and I like to use them occasionally, but, if Kodachrome DID come back, I might buy one roll, out of curiosity, but I would not be a regular user.
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