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Forum: Pentax Price Watch
03-08-2017, 05:20 PM
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I ordered the Series 2 with head based on this post, and it arrived today. Really nice upgrade from my aluminum Bogen 3401 that I've had for maybe 15 years. Thanks.
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Forum: Pentax Price Watch
11-25-2016, 01:45 PM
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The full-frame Rokinon 14mm f/2.8 is on sale for $249.00 from Amazon, B&H, and Adorama (with 2% rewards at the latter two).
I have the Sigma 10-20mm f/4-5.6, but I just bit on one of these for better astrophotography potential, and in case I get a K-1 eventually.
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Forum: Sold Items
09-04-2013, 01:20 PM
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Forum: Sold Items
09-02-2013, 01:02 PM
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PentaxForums.com Marketplace Listing
Item for Sale
Pentax K-7 $250 shipped
Asking Price
250 USD
Item Location
Pennsylvania (United States)
Item Description
Pentax K-7 with 11,569 shutter actuations. I've owned it for about 6 months, and it's served me well. I'm selling because I've upgraded to a K-5 II.
There is one problem with the body: It will not control a P-TTL flash in the hotshoe. The built-in flash works fine, and the built-in flash can be used to control an off-camera flash in P-TTL mode. The hotshoe can fire a manual (non P-TTL) flash.
The body condition is good, with normal wear and tear. The biggest mark is from a QR plate, under the bottom right corner LCD screen (visible in pictures).
Includes box, manuals, software CD, body cap, strap, video cable, battery charger, generic battery. Does NOT include USB cable.
$250 shipped by USPS Priority Mail (domestic).
Are you the original owner of the item being sold?
No
Are you selling or trading this item?
Selling
Item Condition (Key)
Used
Damaged
Shipping Destinations
Worldwide
Shipping Charge
USPS Priority Mail (domestic) included
Shipping Services
USPS, UPS
Accepted Payment Types
PayPal
Return Policy & Additional Details
3 day review period after receipt.
Please send me a private message if interested in the item!
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Forum: Pentax Price Watch
06-11-2012, 12:31 PM
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You can look up the part number at Sandisk's own website, and it's also stated to be UHS-1 there, with the same product pictures.
Edit: The Roman numeral I on the card is a UHS-1 symbol.
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Forum: Pentax SLR Lens Discussion
05-30-2008, 06:04 PM
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Surely it should be a blin lens?
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Forum: Pentax SLR Lens Discussion
05-30-2008, 05:03 PM
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Forum: Photographic Technique
04-18-2008, 05:03 PM
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For most subjects, I use center spot (and recompose) in single AF mode. But for birds in flight, I'll switch to auto-spot and continuous AF. That way, if I don't keep the bird centered, one of the other sensors will pick it up, and as long as I'm shooting against the sky, there's nothing else for the sensors to lock onto. Auto-spot is useless if there's anything in the foreground for it to pick up on. And sometimes if there's anything in the background.
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Forum: Pentax DSLR Discussion
04-11-2008, 07:10 PM
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Noisychip, you're wondering exactly the same things I've been wondering. In a closed-loop system, any problem that produces out-of-focus images should affect all lenses, not just some (though the problem may be more apparent the shallower the DOF is).
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Forum: Digital Processing, Software, and Printing
01-27-2008, 05:56 PM
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BTW, the 3:2 aspect ratio is the same as 35mm film (which had an image area 36x24mm). That's why most DSLRs use this ratio--it's part of their film heritage.
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Forum: Pentax DSLR Discussion
01-15-2008, 06:48 PM
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...and the acceptable circle of confusion.
Since making (for example) an 8x10 print from a smaller format requires more enlargement, the allowable circle of confusion on the film or sensor is smaller. As discussed above, you might tolerate a 0.03mm CoC on 35mm film, but only 0.02mm on APS-C. The depth of field does depend on the format being used. It is not an intrinsic property of the lens.
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Forum: Pentax SLR Lens Discussion
01-15-2008, 03:30 PM
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Maybe Newton's rings from cemented or nearly-adjacent lens elements? (You old darkroom gnomes remember Newton's rings, right?)
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Forum: Photographic Technique
10-06-2007, 03:08 PM
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Stewart, I couldn't agree with you more. A couple of years ago, my wife and I were planning our wedding, and we looked at webpage after webpage of wedding photographers. It was one tilted image after the next. It looked so faddish, which meant to us that wedding pictures in that style would soon look dated.
Eventually we found a photographer whose photos were beautiful and timeless (and shot on B&W film), and we ended up being extremely happy with her work.
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Forum: Weekly Photo Challenges
09-24-2007, 06:27 PM
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A slide show the whole family can enjoy...
I just got my K10D last Wednesday. This came from one of my Canon SLRs a few years back, so maybe it's not eligible. This is from a negative scan (Nikon Coolscan V ED) of B&W film, Ilford HP5+, I think.
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Forum: Pentax DSLR Discussion
09-17-2007, 06:31 PM
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I think we've moved past this point, but I just spent a few minutes making a drawing to illustrate the difference between DOF and background clutter, and gosh darn it, I'm going to use it!
Our subject is Mr. Blue Circle. First we photograph him with a 100mm lens, shown by the black lines. Then we switch to the 50mm lens, and move to half the distance, shown by the red lines.
If we shoot with the same aperture in both cases, the DOF will be the same, which I've illustrated with the green bar alongside the subject. Everything within the bar will be in acceptable focus. (As mentioned previously, this is an approximation and isn't quite true when the DOF is "thick" compared to the subject distance. I probably should have put the cameras further away from Mr. Blue Circle.)
Note that even though the DOF is the same, the 50mm lens includes more trees and other junk in the background, making the background more cluttered.
I think the notion that "shallower DOF = more background blur" comes from the way we learn about DOF. We think of putting the camera on a tripod, mounting a lens, and stopping down that same lens from f/2, f/2.8, f/4, all the way to f/32. The DOF increases, and at the same time the background gets less blurry. We associate these two effects in our head. But switching lenses and shooting at the same aperture isn't the same as keeping the same lens on the camera and stopping it down. When you switch lenses, you can end up with the same DOF and different blur. Or even shallower DOF and less blur, or vice-versa.
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Forum: Pentax DSLR Discussion
09-17-2007, 06:19 PM
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The simple equations assume that the DOF is "thin" compared to the camera-to-subject distance. If you're 10 feet away, and the DOF is 8 feet, the equations break down. Try repeating your experiment with a fast aperture like f/2, and you'll see the DOF is the same, or very close, in the situations you tried.
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Forum: Pentax DSLR Discussion
09-17-2007, 05:58 PM
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You're wrong, in that they will have the same DOF. But you're right in that the telephoto will give a more blurred background. I think you're continuing to equate DOF with the degree of background blur. As I tried to make clear, these are not the same thing.
The DOF tells you how much of the subject is in acceptable focus. It does not tell you about the appearance of the out-of-focus background.
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Forum: Pentax DSLR Discussion
09-17-2007, 04:31 PM
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The LL article is correct. But your title for this thread is wrong. "What is the depth of field (the region of sharp focus)?" and "How blurred is the distant background?" are two different questions.
The article's assertion, that the DOF is the same for any focal length, assuming the subject magnification and f-stop are the same, is correct. Imagine you're photographing your subject with a 100mm lens at f/8. You get a certain depth of field; in this case, say the subject is sharp over a region of 1 foot, front to back. You switch to a 50mm lens. Your experience tells you that the shorter lens has more DOF, and that's true in a sense. But to photograph your subject at the same size, you have to move in to half the distance, compared to when you were using the 100mm lens. Shortening the camera-to-subject distance reduces the DOF, and exactly offsets the DOF you gained by switching lenses. Once you've switched lenses and moved closer, there's still a 1-foot-deep region of the subject that's sharp at f/8.
But the distant background is outside the DOF either way. And the 50mm lens "takes in" more background than the 100mm, so the background is more cluttered than with the 100mm. This leads to the subject being less isolated from the background, but that's not the same as saying the DOF is larger. You can see this in the article's shots. The longer focal lengths clearly have less clutter in the background than the shorter focal lengths.
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Forum: Sold Items
09-15-2007, 12:40 PM
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Forum: Sold Items
09-11-2007, 01:52 PM
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Hi,
If your mirror lens is still available, I'll buy it.
Great prices, BTW. I bought a Tamron 1.4x from a guy here for $65 shipped, and I thought that was a great deal. If yours doesn't go in a flash, people are crazy.
Thanks,
Matt
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Forum: Sold Items
09-10-2007, 03:15 PM
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This lens is still available.
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Forum: Sold Items
09-08-2007, 11:47 AM
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I bought this lens on eBay without realizing it was a screwmount (my fault). I'm not interested in using an adapter at this time, so I have not tried it on a camera. I used to have the same lens in Canon FD mount and was very pleased with it.
The aperture appears snappy when I use the pin to stop it down. The focus action is nice and smooth. The glass is clean and scratch-free. There is one internal dust speck that I can see, which unfortunately didn't show up in the photograph above. Externally, the lens shows only normal wear, with some residue from the removal of one of those gold oval inspection stickers (just visible near the top of the photo). The built-in lens hood offers a good amount of friction (it does not lock into place, but I don't think it's supposed to). Front and rear caps are included.
$35 shipped within the United States. Will consider shipping outside the country, to people with a track record here (US$30 + actual shipping costs).
Thanks for looking.
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Forum: Photographic Technique
09-06-2007, 06:40 PM
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TaoMass, I'll play along with your hijacking :lol:. I can sympathize with your viewpoint, because I think some things people do result in "graphic art" rather than "photography". But I don't think HDR is necessarily one of them. By way of example, let me show you the extreme frames from my first HDR effort. It was a technical exercise, and artistically worthless, but here goes:
 
The contrast range was so extreme that I could not make a tone-mapped image that was at all satisfactory using qtpfsgui. Yet when I was standing behind the camera, my eyes could see detail in both the basement shadows and the sky outside. The "straight" images from my digicam are in no way honest representations of what I perceived standing there. The human eye has far more dynamic range than either film or digital camera sensors.
It is certainly possible to take it too far, just as one can crank up the saturation too far. Heck, sometimes Velvia was "dishonest" to my eye. But I think HDR can serve us well when we try to overcome our equipment's limitations, and fully capture our perception of the scene in front of us.
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Forum: Sold Items
09-04-2007, 06:38 PM
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I think the doubled aperture scale is because of the interchangeable mount. Some cameras have the aperture ring turning one way, and others have it turning the other. So if you put a Canon FD mount on this lens, for example, it would probably use other other set of numbers.
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Forum: Pentax DSLR Discussion
08-15-2007, 11:50 AM
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Since focusing (and composing the scene) occurs with the lens wide open, that's all that matters. If you have your 50mm f/1.4 lens mounted, it doesn't matter if you're shooting at f/1.4 or f/16--you're focusing at f/1.4 either way and will be fine.
Blackout tends to be a problem when you have a slow lens, like a f/5.6 telephoto, and add teleconverters, making it an f/8 or f/11 lens wide open.
On the pictures you included:
The drummer picture seems to have a plane of sharp focus that's in front of the head. Look at the shiny rim of the drums. I don't think motion blur is a big problem in this one, because there's not a whole lot of blur in the drumsticks, which presumably were moving quickly (compared to the face). So, yeah, chalk that up to focus error.
In the second one, there's reasonably sharp focus on the girl's ring. I would think the face of the girl nearest the camera would be in about the same plane, suggesting motion blur is the problem, but it's hard to tell.
In the third one, the girl's face looks reasonably sharp. The guy's isn't, but his shirtsleeve is pretty good. Chalk that one up to shallow depth-of-field.
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