Re: extension tube question
Cory Waters wrote: The el-cheepo extension tubes online are totally dumb. By that I mean they don't have any electrical contacts and whatnot. With the newer DSLRs and the crippled mount or whatever, I would assume one would really want a set of tubes that's A compliant. Maybe I'm wrong about that though since Even the $180 versions that are on BH's site (on backorder maybe forever) are only K versions. So, Dos one just buy the cheep-o versions from Ebay, use lenses with aperture rings, and use the green button method? I bought a set of Vivitar's from ebay that had all the electrical contacts including AF when I had an *ist D. since there are no optical elements in the tubes, I wasn't concerned about brand. Christian -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: extension tube question
- Original Message - From: Cory Waters Subject: extension tube question So, Dos one just buy the cheep-o versions from Ebay, use lenses with aperture rings, and use the green button method? Thats the way I do it, though I use bellows, not extension tubes. The principle is similar though. I've had enough problems with stop down metering on the k10/K20 that I would tend to not trust anything that knocks the amount of light down, either by stop down metering or extending a lens out to allow for accurate metering. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: extension tube question
Kenko sells a set with full contacts, (I think they make one with a screwdriver pass through as well). You can usually get the full contact version for between $150 and $175 in a camera store if they're in stock. I'd expect a better price on line somewhere. Cory Waters wrote: The el-cheepo extension tubes online are totally dumb. By that I mean they don't have any electrical contacts and whatnot. With the newer DSLRs and the crippled mount or whatever, I would assume one would really want a set of tubes that's A compliant. Maybe I'm wrong about that though since Even the $180 versions that are on BH's site (on backorder maybe forever) are only K versions. So, Dos one just buy the cheep-o versions from Ebay, use lenses with aperture rings, and use the green button method? CW Tried to use jedi mind tricks to get Nico to forget he'd loaned his D-FA 100 macro but it didn't work. -- Vote for Cthulhu. Why settle for a lesser evil... -- Dr. Jerry Pournelle -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Extension Tube Question
Collin Brendemuehl let his curiosity get the best of him when he asked: I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it? Kenko makes an AF tube for Pentax. I have one but I've found very little use for the AF capabilities. In my experience, AF can't handle the precise focusing requirements in macro work. It might be useful when coupled with an AF telephoto when you want to get closer than the lens' minimum focusing distance. I don't have an AF tele to try it with (yet). IMO, you'd be ruining a good TC for something you'd very rarely need. Tom Reese
Re: Extension Tube Question
Collin Brendemuehl wrote: I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it? Doesn't a TC alter the lens aperture information provided to the body? S
Re: Extension Tube Question
On Jun 22, 2005, at 8:08 AM, Tom Reese wrote: I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it? Kenko makes an AF tube for Pentax. I have one but I've found very little use for the AF capabilities. In my experience, AF can't handle the precise focusing requirements in macro work. It might be useful when coupled with an AF telephoto when you want to get closer than the lens' minimum focusing distance. I don't have an AF tele to try it with (yet). I agree with Tom: AF in an extension tube is mostly inconsequential. When I'm using tubes, I want a tripod and a fine geared rackmount for stability and precision focusing. Godfrey
Re: Extension Tube Question
On Jun 22, 2005, at 7:59 AM, Steve Jolly wrote: Collin Brendemuehl wrote: I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it? Doesn't a TC alter the lens aperture information provided to the body? No. Light falls off as you add lens extension by the amount dictated in the Inverse Square Law, but the aperture doesn't change. A TTL meter simply reads less light. Godfrey
Re: Extension Tube Question
On Wed, Jun 22, 2005 at 08:44:28AM -0700, Godfrey DiGiorgi wrote: On Jun 22, 2005, at 7:59 AM, Steve Jolly wrote: Doesn't a TC alter the lens aperture information provided to the body? No. [...] Godfrey The Pentax 1.7x AF adapter does alter the maximum aperture information; it shows my 300/2.8 wide open as f4.5 But it's the exception; I don't know of any other TCs that do this. A full AF TC, with the digital signal pin contact, is unlikely to be able to change aperture information; Pentax haven't released a specification for how lens-to-body digital signals are encoded.
Re: Extension Tube Question
The Pentax 1.7x AF adapter does alter the maximum aperture information; it shows my 300/2.8 wide open as f4.5 Very interesting! thanks john. Godfrey But it's the exception; I don't know of any other TCs that do this. A full AF TC, with the digital signal pin contact, is unlikely to be able to change aperture information; Pentax haven't released a specification for how lens-to-body digital signals are encoded.
Re: Extension Tube Question
- Original Message - From: Collin Brendemuehl Subject: Extension Tube Question I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it? AF is gonna be pretty useless with tubes, so why bother? William Robb
Re: Extension Tube Question
Kenko has a 25mm one. they don't make the 12mm in Pentax mount. Herb - Original Message - From: Collin Brendemuehl [EMAIL PROTECTED] To: pentax-discuss@pdml.net Sent: Wednesday, June 22, 2005 10:40 AM Subject: Extension Tube Question I've seen A-class extension tubes. But does anyone make one with the AF mechanism coupled through? Or would it be better to take a little 1.4xTC and strip the optical guts out of it?
RE: Extension tube K
Fantastic!!! Thanks a lot!!! I think I'll give it a try with TTL cameras first. Cheers Guys!!! Andy -Original Message- From: John Coyle [mailto:[EMAIL PROTECTED] Sent: Sunday, January 04, 2004 10:00 AM To: [EMAIL PROTECTED] Subject: Re: Extension tube K Andy, the basic formula for calculating the additional exposure required is given in this table (taken from The Asahi Pentax Guide, Focal Press 1967): Tube No Magnification Exposure factor 1.0.35x1.8 2.0.52x2.3 3.0.69x2.9 1+3.0.86x3.5 2+3.1.04x4.1 the assumption is you are using a 55mm lens focussed at 18in. The factors may vary slightly for the K tubes, but this may get you going in the right direction! . John Coyle Brisbane, Australia - Original Message - From: Andy Chang [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Saturday, January 03, 2004 11:12 PM Subject: Extension tube K Hi guys, A belated Happy holiday to you all!!! I have just acquired a Pentax Extension Tube set K. I had no idea what it does first but after looking at Boz's web site, I have some idea how it works. It was a bargain and I couldn't resist bidding for it. According to Boz's site, it is a manual extension tube set and I guess the differences between the Auto set and the manual set is about the A position on the A and later lenses. If you remember, I have asked about losing F stops using teleconverter. I'm just wondering if it also applies on the extension tubes. By adding extension tubes behind the lens, do I have to adjust the exposure accordingly? Thanks Andy
RE: Extension tube
Thank you Ian, Your advice is most welcomed and hopefully I can make good use to those extension tubes. It is more of an experiment than a sort of have-to-use basis since I have purchased a 100/2.8 macro to do most of my macro work. And it has served me exceptionally well. I'm fairly new to macro work (naturewise) since I had been taking shots of products or close-up of products in a room without the nature interfering with the shots. But as a biologist, I do like to take pictures of the wild and especially the little things which we usually missed (I can't take photos of bacteria even though I am a microbiologist grin, that'll take more than a macro lens...) I hope I can start getting some good pictures and put it up in PUG to share with all of you! I can't believe I only found you guys a few months ago What was I doing all these years? Cheers Andy -Original Message- From: Ian bromehead [mailto:[EMAIL PROTECTED] Sent: Sunday, January 04, 2004 11:42 AM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Subject: RE: Extension tube Andy I am just as gullible as you, and couldn't resist buying one of these sets On ebay. I bought the Extension Tube K set, which is A compatible to stop down the aperture But no auto-focus compatibility So far I don't regret it, but they are clearly less practical than a good macro. Just before I read your pdml email this morning, I was outside relaxing in the morning california sunshine. I spied heavy dew on the leaves behind me and used them to take a few photos. My biggest learning by trial and error has been that of DOF. Clearly this is one way to really understand how to use and control DOF and the necessity to take one's time in composition and think carefully in your mind's eye where to stand vs natural light to get the right image content. The guy I bought them from advised me to see ...the ultimate book for macro photography is John Shaw's Closeups in Nature. It's a great read and has wonderful photos too.. I have yet to purchase it, but he's probably right. I bought a small tripod which is absolutely essential for work with them in all cases. Also I picked up tips from folks much more experienced than I on this and other pdml's. Tips such as using cardboard to shield the subject from winds and draughts, crucial given the highly restrictive DOF. I saw Rod's reply to you, and thought it might be useful to give you my experience, which as he says is probably lens dependant. For f stops I have found that I loose 0.6EV sequentially with each unit, used mostly with my SMC-n 50mm, 1:1.7. Just to remind myself of this, I re-tested again today. @ ISO 200, I focused at f16, 1/125mm on a neutral subject in full sun. I then inserted ET K tube 1, lost 0.6EV, and subsequently lost 0.6EV for ETK tube 2, and 1 full stop when I added ETK tube 3 which is the longest. How much you loose will depend on which sequence you use these in, you doint have to use them in this sequence of course. I use a PZ-1P and an older Kodak Dc280 digital. Clearly the capacity to mess with glass and accessories is missing from the fixed, snapshot digital, but the capacity to make mistakes and throw them away is attractive with digital, and I miss it. So I'm really anxious to see prices come into my range before I'll switch to SLR digital. In between times, the PZ-1P is a wonderful instrument, solid and big enough even when fixing the extension tubes with a long telephoto or my Tamron 28-300mm zoom. It makes for a long lever in front of the camera, but the PZ-1P is a hefty build so I don't have any issues, and a tripod is required of course. Welcome to macro photos, see some of my work in my portfolio on photo.net, not sure exactly How to direct you. Cheers Ian Date: Sat, 3 Jan 2004 21:12:22 +0800 From: Andy Chang [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Extension tube K Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi guys, A belated Happy holiday to you all!!! I have just acquired a Pentax Extension Tube set K. I had no idea what it does first but after looking at Boz's web site, I have some idea how it works. It was a bargain and I couldn't resist bidding for it. According to Boz's site, it is a manual extension tube set and I guess the differences between the Auto set and the manual set is about the A position on the A and later lenses. If you remember, I have asked about losing F stops using teleconverter. I'm just wondering if it also applies on the extension tubes. By adding extension tubes behind the lens, do I have to adjust the exposure accordingly? Thanks Andy
Re: Extension tube K
On 3 Jan 2004 at 21:12, Andy Chang wrote: If you remember, I have asked about losing F stops using teleconverter. I'm just wondering if it also applies on the extension tubes. By adding extension tubes behind the lens, do I have to adjust the exposure accordingly? Yes, consider the way the tubes work. When using tube the image projected on the film plane is only a sub section of the image that would appear if the lens were closer (hence the effective magnification). You can then assume that the available illumination in that projected image is less over the area of the film as it is spread over a wider area. You can calculate the losses but it's difficult and lens dependent to an extent, this is one of the areas where TTL meters reign supreme. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications/ Pentax user since 1986, PDMLer since 1998
Re: Extension tube K
Rob Studdert said, about extension tubes: You can calculate the losses but it's difficult and lens dependent to an extent, this is one of the areas where TTL meters reign supreme. Not difficult really, so much as _annoying_. But yeah, this is one place where having TTL metering is soo nice. That's one of the things I liked about having a Spotmatic -- since my bellows and my extension tubes are screwmount, I need to replace either the Spotmatic or the screw-to-K converter (yes, that got stolen too) so I can shoot macro with less calculation again. But you still have to do the math when you use a flash, unless you also have TTL-flash mode available. (I guess the PZ-10 will do that for me, if I get the converter.) My bellows has a scale engraved on it so that you can just look up the exposure factor for a given extension ... as long as you've got a 50mm lens attached (with some fudging for the in-between amounts, of course). -- Glenn
RE: Extension tube
Andy I am just as gullible as you, and couldn't resist buying one of these sets On ebay. I bought the Extension Tube K set, which is A compatible to stop down the aperture But no auto-focus compatibility So far I don't regret it, but they are clearly less practical than a good macro. Just before I read your pdml email this morning, I was outside relaxing in the morning california sunshine. I spied heavy dew on the leaves behind me and used them to take a few photos. My biggest learning by trial and error has been that of DOF. Clearly this is one way to really understand how to use and control DOF and the necessity to take one's time in composition and think carefully in your mind's eye where to stand vs natural light to get the right image content. The guy I bought them from advised me to see ...the ultimate book for macro photography is John Shaw's Closeups in Nature. It's a great read and has wonderful photos too.. I have yet to purchase it, but he's probably right. I bought a small tripod which is absolutely essential for work with them in all cases. Also I picked up tips from folks much more experienced than I on this and other pdml's. Tips such as using cardboard to shield the subject from winds and draughts, crucial given the highly restrictive DOF. I saw Rod's reply to you, and thought it might be useful to give you my experience, which as he says is probably lens dependant. For f stops I have found that I loose 0.6EV sequentially with each unit, used mostly with my SMC-n 50mm, 1:1.7. Just to remind myself of this, I re-tested again today. @ ISO 200, I focused at f16, 1/125mm on a neutral subject in full sun. I then inserted ET K tube 1, lost 0.6EV, and subsequently lost 0.6EV for ETK tube 2, and 1 full stop when I added ETK tube 3 which is the longest. How much you loose will depend on which sequence you use these in, you doint have to use them in this sequence of course. I use a PZ-1P and an older Kodak Dc280 digital. Clearly the capacity to mess with glass and accessories is missing from the fixed, snapshot digital, but the capacity to make mistakes and throw them away is attractive with digital, and I miss it. So I'm really anxious to see prices come into my range before I'll switch to SLR digital. In between times, the PZ-1P is a wonderful instrument, solid and big enough even when fixing the extension tubes with a long telephoto or my Tamron 28-300mm zoom. It makes for a long lever in front of the camera, but the PZ-1P is a hefty build so I don't have any issues, and a tripod is required of course. Welcome to macro photos, see some of my work in my portfolio on photo.net, not sure exactly How to direct you. Cheers Ian Date: Sat, 3 Jan 2004 21:12:22 +0800 From: Andy Chang [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Extension tube K Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi guys, A belated Happy holiday to you all!!! I have just acquired a Pentax Extension Tube set K. I had no idea what it does first but after looking at Boz's web site, I have some idea how it works. It was a bargain and I couldn't resist bidding for it. According to Boz's site, it is a manual extension tube set and I guess the differences between the Auto set and the manual set is about the A position on the A and later lenses. If you remember, I have asked about losing F stops using teleconverter. I'm just wondering if it also applies on the extension tubes. By adding extension tubes behind the lens, do I have to adjust the exposure accordingly? Thanks Andy
Re: Extension Tube Question
On Sat, 15 Mar 2003 20:16:10 -0700, you wrote: Does anyone have the Kenko Uniplus Tube 25 for Pentax? The web site (thkphoto) says it is designed for autofocus, but doesn't specifically say that autofocus lenses can still autofocus with it on. Does anyone know? Keeping fingers crossed. This would answer a pressing need for closer focusing with my Sigma 70-200 f2.8. Thanks, Joe It has the Pentax AF drive pin. It allows autofocus. I've used it in autofocus mode my FA* 600/f4, F* 300/f4.5, and PZ1p. Of course, you lose infinity focus, but that occurs with any extension tube. -- John Mustarde www.photolin.com
