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09-16-2010, 06:00 AM   #16
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you need to look carefully at manual focus lenses before you try them, for a couple of reasons.

Depending on lens maker, the focusing throw can vary a lot. Some lenses may have as little as 1/4 turn, (90 degrees) others may have nearly a full turn (approacing 360 degrees)

While the longer focusing throw is much more precise, it is difficult to change focusing ranges quickly. You have to learn to prefocus close to whare yoou want to be, as opposed to trying to aquire focus in an instant. It takes practice.

For stationary subjects the longer focusing throw is better because you have the time to be very very accurate.

The best compromise lens I have is a Vivitar Series 1 70-210 F3.5, (version 1 of the lens) This lens is a single ring zoom, with a 180 degree focusing throw. The throw is short enough to quickly aquire focus, but long enough to be relitively accurate. Being a one ring zoom, you can also focus and zoom all in one motion to track moving subjects, and it is a true zoom, meaning that it holds focus as you zoom, as opposed to a "verifocal" lens which does not. If you want to really learn manual focus, on a medium tele zoom this would be my choice. BUT be warned, it weighs 9 pounds, so it is not a light lens. Also it is a manual aperture, and depending on camera, metering can be a bit "interesting"

09-16-2010, 06:06 AM   #17
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QuoteOriginally posted by RioRico Quote
At 24-28-35mm, f/2 glass is fairly expensive, and f/2.8 manual primes are pretty cheap and common. And good Fast Fifty's are still dirt cheap.
I am planning to get the new 35 mm F2.4 AF lens and also keep my eyes open for an used A 50 mm F1.7 MF lens (or a new F1.4 AF...).
09-16-2010, 06:54 PM   #18
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Many thanks for all the responses -- this forum rocks !
09-16-2010, 07:29 PM   #19
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QuoteOriginally posted by SpecialK Quote
If your subjects are not moving, like a building or landscape, then manually focusing is not so bad. However, once your subject starts moving, catching the proper focus becomes more difficult.

Many people on this forum only have manual lenses.
I disagree SpecialK. I do the vast majority of my hummingbird and waterfowl shots with a manual focus Vivitar 135 2.8. I find it easier because I can focus the lens faster than my camera does. The autofocus lenses I have are in my signature and they are good lenses...but...I have not had good luck with Pentax's ability to focus on fast moving objects. As such, I've pretty much moved exclusively to manual lenses. Yes, I can use all of my lenses in manual mode (and do at times), but I find the pure manual focus lenses easier to focus.

If you get manual lenses, start out with a cheap lens off ebay or this forum. You can usually pick up 135mm lenses for very cheap ($10-20 plus shipping). I'd suggest starting with that to figure out if you like that over auto focus because it is personal preference.

After you get it, you'll need a couple weeks to mess around with the functionality. Start slow, use a tripod for things that don't move, and work your way up. While I find I get better results from manual focus, I've seen many people who get really good results from auto-focus lenses. You need to find out which works best for you and your camera.

If you are shooting moving objects, start off with positioning your shot. If you are shooting something that will pass a specific spot (like a race car), focus on that one spot with the right ISO and aperture and wait for the shot. After you've practiced for some time, you'll learn how to track and focus manually at the same time.

09-16-2010, 07:30 PM   #20
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QuoteOriginally posted by Lowell Goudge Quote
you need to look carefully at manual focus lenses before you try them, for a couple of reasons.

Depending on lens maker, the focusing throw can vary a lot. Some lenses may have as little as 1/4 turn, (90 degrees) others may have nearly a full turn (approacing 360 degrees)

While the longer focusing throw is much more precise, it is difficult to change focusing ranges quickly. You have to learn to prefocus close to whare yoou want to be, as opposed to trying to aquire focus in an instant. It takes practice.

For stationary subjects the longer focusing throw is better because you have the time to be very very accurate.

The best compromise lens I have is a Vivitar Series 1 70-210 F3.5, (version 1 of the lens) This lens is a single ring zoom, with a 180 degree focusing throw. The throw is short enough to quickly aquire focus, but long enough to be relitively accurate. Being a one ring zoom, you can also focus and zoom all in one motion to track moving subjects, and it is a true zoom, meaning that it holds focus as you zoom, as opposed to a "verifocal" lens which does not. If you want to really learn manual focus, on a medium tele zoom this would be my choice. BUT be warned, it weighs 9 pounds, so it is not a light lens. Also it is a manual aperture, and depending on camera, metering can be a bit "interesting"
That's an extremely good point and exactly why I love my Vivitar 135. The throw on it works very well for me...but I also think that's specific to each photographer. That's why I suggested a cheap lens to learn on (or a couple if affordable).
09-17-2010, 05:57 AM   #21
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One last point.

If you are going to go for manual focus lenses in a big way, especially a FAST lens like the samyang (AKA vivitar, pro-optic, bower rokonon etc...) 85mmF1.4 then you need to consider as well a split image vinder.

The standard focusing screen has a higher dof than fast lenses, making accurate focus difficult.
09-17-2010, 04:52 PM   #22
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QuoteOriginally posted by Lowell Goudge Quote
The best compromise lens I have is a Vivitar Series 1 70-210 F3.5, (version 1 of the lens) ... BUT be warned, it weighs 9 pounds, so it is not a light lens. Also it is a manual aperture, and depending on camera, metering can be a bit "interesting"
You must have the Solid Platinum version of the S1V1. Mine weighs 880g, just under two (2) pounds. On Earth, anyway. On Jupiter, it would be about 4.5 pounds. Are you in a centrifuge, by any chance?

QuoteOriginally posted by Lowell Goudge Quote
The standard focusing screen has a higher dof than fast lenses, making accurate focus difficult.
Another focus option is Catch-In-Focus aka Trap-Focus. It's useful with my faster cheap manual lenses (55/1.4, 85/2, 135/2.5, etc).
02-22-2014, 04:24 PM   #23
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QuoteOriginally posted by RioRico Quote
And there's a trick for using CIF with an AF lens. Just ask.
If this doesn't involve shorting one of the contacts, please do share what the trick is.

02-22-2014, 04:28 PM   #24
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QuoteOriginally posted by wysz Quote
If this doesn't involve shorting one of the contacts, please do share what the trick is.
All tricks involve shorting one or more of the contacts and/or use of a Dremel tool.


Steve
02-24-2014, 09:19 AM   #25
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I am in the same boat, kind of. I have had my KX for about a year and been using my Tamron 28-300mm with it all the time. I read that manual focusing was better than AF so I started doing that and haven't used AF but I am wondering if I should just us the AF, because I shoot mostly kids and families with small kids and my pictures that actually turn out are very slim because of me having to manual focus all the time. I just feel I have more control opposed to the AF mode. Now that I am shopping for a new lens on budget I'm considering a new portrait lens but the old 50mm 1.7 but I always shoot in AV mode and wonder if this would even be possible or if I should just make my life easier and just get the da 50mm 1.8. Thoughts?? Thank you.
02-24-2014, 09:48 AM   #26
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Dunno if it got mentioned somewhere above, but just a reminder that with MF lenses the camera asks you for focal length when you turn it on and uses that for shake reduction and also to calculate the automatic exposure controls for shutter speed (shorter focal length allows slower speed). That allows shake reduction and auto modes to work fine with A series primes, but its a mess with zooms, as soon as you zoom its either over or under correcting the image neither of which are good for clarity.
The place to change focal length is so idiotically buried in the menus that its not even an option to change it for every shot with a different zoom setting. On a short zoom like my 24-50 you can pick a middle focal length as a compromise but I wouldn't try that on something that spans 100+mm of focal length.
You can just turn SR off, but unlike the old film cameras, you tend to be able to clearly see it even with steady hands as a slight lack of sharpness in many photos, possibly one of the reasons new AF lenses generally seem sharper.
I find myself more and more using AF lenses on the DSLR and MF lenses on my film cameras. Though I do often shoot on M mode with no SR with the MF zooms I have. Sometimes I just set the lenses longest focal length at start up and only turn on SR when using it at that focal length on distant stuff since that's where there is the most shake anyways. At least SR on/off is easy to access fast on all the cameras. I would love to see them add the option to switch something useless on the INFO menu with a focal length setting you can change with the rear dial, that would make it fast enough access to actually use it.
Also I do not consider flipping the camera on and off every time I want to change focal length an acceptable way of changing it for wear reasons if nothing else.
Actually with the lack of aperture coupling and no easy access to focal length adjustments Pentax does a rather crappy job of supporting older lenses, which last I checked was one of their selling points.
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