Re: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
Yes, there is no problem with this lens reporting the proper focal length in EXIF. My "shake reduction" question was the result of an unfortunate leap in logic. I think I'm going to like this lens. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
From: John Francis On Fri, May 25, 2012 at 02:30:57PM -0400, John Sessoms wrote: From: Darren Addy I'm curious... if it shows up in Photoshop as a Pentax-F 35-105mm, does that mean that it is also misreading the focal length that this lens is set at (when doing image stabilization)? If it is doing image stabilization for a 105mm focal length when the lens is set to 200mm, that could definitely lead to some lack of sharpness. I think I will see if I get better results with Image Stabilization off and tripod mount it (which I guess I should be doing to test for sharpness anyway!). I don't know. I think the camera just has to have some kind of a code to bury in the EXIF to identify the lens & it uses the code that PhotoShop thinks is the Pentax-F 35-105. Don't blame the camera - it just reports the code it gets from the lens. Some manufacturers (most notably Sigma) didn't request a code from Pentax (presumably because there was a cost involved), so just used the same code for multiple lenses (usually one that corresponded to a Pentax lens that was similar to the first lens). I'm a little surprised to see that Tokina did this - they used to be a Pentax partner, so I'd expect them to get it right). As for the original query: it should be pretty easy to confirm that the reported focal length is correct - that information is also in the EXIF. When I mount this on my K20D, it shows the correct focal length in the image information when I review images on the LCD. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
On Fri, May 25, 2012 at 02:30:57PM -0400, John Sessoms wrote: > From: Darren Addy > > >I'm curious... if it shows up in Photoshop as a Pentax-F 35-105mm, > >does that mean that it is also misreading the focal length that this > >lens is set at (when doing image stabilization)? > >If it is doing image stabilization for a 105mm focal length when the > >lens is set to 200mm, that could definitely lead to some lack of > >sharpness. I think I will see if I get better results with Image > >Stabilization off and tripod mount it (which I guess I should be doing > >to test for sharpness anyway!). > > I don't know. > > I think the camera just has to have some kind of a code to bury in > the EXIF to identify the lens & it uses the code that PhotoShop > thinks is the Pentax-F 35-105. Don't blame the camera - it just reports the code it gets from the lens. Some manufacturers (most notably Sigma) didn't request a code from Pentax (presumably because there was a cost involved), so just used the same code for multiple lenses (usually one that corresponded to a Pentax lens that was similar to the first lens). I'm a little surprised to see that Tokina did this - they used to be a Pentax partner, so I'd expect them to get it right). As for the original query: it should be pretty easy to confirm that the reported focal length is correct - that information is also in the EXIF. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
The camera uses the code recorded in the data chip in the lens. Having partially disassembled an FA and an F lens I can say with relative assurance that that focal length is reported by several conductive strips that are sampled differently as the zoom ring is turned. I expect that the reported focal length is most likely correct. The Acontacts tell the camera the absolute maximum and minimum apertures the lens is capable of, (as per Boz K mount description page). Now I don't know how the following is done, but based on behavior I'd say the lens' on board chip sends a modification signal to the camera body based on the focal length selected so the camera will display and record the correct f stop. This doesn't happen with A zoom lenses since they have no chip. On 5/25/2012 2:30 PM, John Sessoms wrote: From: Darren Addy I'm curious... if it shows up in Photoshop as a Pentax-F 35-105mm, does that mean that it is also misreading the focal length that this lens is set at (when doing image stabilization)? If it is doing image stabilization for a 105mm focal length when the lens is set to 200mm, that could definitely lead to some lack of sharpness. I think I will see if I get better results with Image Stabilization off and tripod mount it (which I guess I should be doing to test for sharpness anyway!). I don't know. I think the camera just has to have some kind of a code to bury in the EXIF to identify the lens & it uses the code that PhotoShop thinks is the Pentax-F 35-105. I don't know why it wouldn't use the code for the FA* 80-200/2.8 ED [IF]? But it apparently doesn't I just did a quick test on mine with the K20D & when you press the INFO button, it shows the correct focal length - 80 = 80, 200 = 200 and in between shows proportional focal lengths in between. -- Don't lose heart! They might want to cut it out, and they'll want to avoid a lengthily search. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
From: Darren Addy I'm curious... if it shows up in Photoshop as a Pentax-F 35-105mm, does that mean that it is also misreading the focal length that this lens is set at (when doing image stabilization)? If it is doing image stabilization for a 105mm focal length when the lens is set to 200mm, that could definitely lead to some lack of sharpness. I think I will see if I get better results with Image Stabilization off and tripod mount it (which I guess I should be doing to test for sharpness anyway!). I don't know. I think the camera just has to have some kind of a code to bury in the EXIF to identify the lens & it uses the code that PhotoShop thinks is the Pentax-F 35-105. I don't know why it wouldn't use the code for the FA* 80-200/2.8 ED [IF]? But it apparently doesn't I just did a quick test on mine with the K20D & when you press the INFO button, it shows the correct focal length - 80 = 80, 200 = 200 and in between shows proportional focal lengths in between. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
On Thu, May 24, 2012 at 4:33 PM, Derby Chang wrote: > > I have one. Lovely, though weighty lens. And, yes, mine also makes a sound > when I roll it, like there ball bearing in there. Bought it last century, > and it's still working fine That is good to hear! (Your report, not the sound in the lens).Thanks for letting me know. Yep, there's a bit of heft in that lens but the way I look at it... some people spend good money to lift weights at the local spa while I get my workout in for free. (Alsothe workout warriors don't get f2.8 with their dumbbells). -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
I have one. Lovely, though weighty lens. And, yes, mine also makes a sound when I roll it, like there ball bearing in there. Bought it last century, and it's still working fine On 24/05/2012 1:55 AM, Darren Addy wrote: I've got my first "pro" lens in this range, but at first blush I'm not very impressed with it. I'm not sure if there is something wrong with it (it makes a noise when I rotate it, which I don't think is Good). Before I send it in for service, I'd like to try the front/back focus adjustment. However, I'm not sure I understand the whole process yet and whether the K-5 can "remember" this lens. Does anyone know if this lens has a "Lens ID" that communicates with the body so the setting can be remembered? If doing the adjustment doesn't solve the problems, I'm going to have to see what it will cost to get this thing serviced. I've read good reports about this lens, and although it is heavy that's a property of its construction and the big glass it contains to get you the constant f2.8. -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
On Wed, May 23, 2012 at 2:45 PM, John Sessoms wrote: > I presume when you say "it makes a noise when I rotate it", that you mean > when you rotate the zoom ring? > > It shouldn't make any noise. It's a really sturdy, pro-quality build lens. > > It shows up in Photoshop as a smc PENTAX-F 35-105mm F4-5.6. Thank you for your kind reply, John. No, I mean that if I take the lens in my hand and roll my wrist, I can hear a strange sound coming from about the middle of the lens. Googling this, I found another person complaining of the same issue and he said that he sent it in for service and when he got it back it still did the same thing. I guess I don't care so much if the lens performs as it should. I'm building a little DIY LensAlign clone so I can adjust for any front/back focus issues with it and see if I can get the truly sharp images that people say this lens normally gives you. If not, I'll have to assume that something is out of whack in there and send it in for servicing. I'm curious... if it shows up in Photoshop as a Pentax-F 35-105mm, does that mean that it is also misreading the focal length that this lens is set at (when doing image stabilization)? If it is doing image stabilization for a 105mm focal length when the lens is set to 200mm, that could definitely lead to some lack of sharpness. I think I will see if I get better results with Image Stabilization off and tripod mount it (which I guess I should be doing to test for sharpness anyway!). -- 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: Tokina AT-X 828 AF PRO 80-200mm f/2.8 question
From: Darren Addy I've got my first "pro" lens in this range, but at first blush I'm not very impressed with it. I'm not sure if there is something wrong with it (it makes a noise when I rotate it, which I don't think is Good). Before I send it in for service, I'd like to try the front/back focus adjustment. However, I'm not sure I understand the whole process yet and whether the K-5 can "remember" this lens. Does anyone know if this lens has a "Lens ID" that communicates with the body so the setting can be remembered? If doing the adjustment doesn't solve the problems, I'm going to have to see what it will cost to get this thing serviced. I've read good reports about this lens, and although it is heavy that's a property of its construction and the big glass it contains to get you the constant f2.8. I presume when you say "it makes a noise when I rotate it", that you mean when you rotate the zoom ring? It shouldn't make any noise. It's a really sturdy, pro-quality build lens. It shows up in Photoshop as a smc PENTAX-F 35-105mm F4-5.6. -- 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.
