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Comment by Banjo posted on Asahi Pentax 6x7: some questions. at 02/11/2010 - 03:34
Would this link provide something useful to the discussion?
http://www.pentaximaging.com/files/manual/6x7_Auto_Extension_Tubes.pdf
http://www.pentaximaging.com/files/manual/6x7_Auto_Extension_Tubes.pdf
Comment by Banjo posted on Extension Tubes at 01/11/2010 - 06:11
BTW, an image of the camera may be found here:
http://www.mrmartinweb.com/images/camera/medium/pentax6x7lg.jpg
http://www.mrmartinweb.com/images/camera/medium/pentax6x7lg.jpg
Comment by Banjo posted on Asahi Pentax 6x7: some questions. at 31/10/2010 - 23:53
Hi all,
I am having an extended look at an Asahi Pentax 6x7 (it looks to me to be the original 1969 model without MLU) in very reasonable but well used (not abused) working condition: it shows brassing on all corners and along some edges. The mirror is exceptionally clean and there is no obvious mould or rubbish in the viewfinder or elsewhere on the body. All the leatherette seems to be in almost like new condition. The asking price is acceptable (providing it all works).
It comes with an SMC Takumar 200/4 lens, which is also very clean inside, the diaphragm, focus ring all very smooth and all the click-stops and stop-down lever, shutter and film advance function well.
One problem: compared to my Gossen Lunasix-3 (and, also, to the Sunny 16 Rule), the TTL lightmeter seem to give/result in readings that (presumably) underexpose to hell ; e.g. for ISO 400 film in bright sun, it suggests about f/22 @ 1/1,000 (a long cry from f/16 @ 1/400? Is this something that could be fixed? (I've been assuming the camera.lens functions in open aperture metering (a la Asahi Pentax Spotmatic SP-F), am I right?)
Thanks in advance for responding.
Second question: I see there are 6x7 SMC Takumar lenses and SMC 67 Pentax lenses: will the Asahi Pentas 6x7 accept the later(?) Pentax 67 lenses or not?
Thanking you in advance for responding.
I am having an extended look at an Asahi Pentax 6x7 (it looks to me to be the original 1969 model without MLU) in very reasonable but well used (not abused) working condition: it shows brassing on all corners and along some edges. The mirror is exceptionally clean and there is no obvious mould or rubbish in the viewfinder or elsewhere on the body. All the leatherette seems to be in almost like new condition. The asking price is acceptable (providing it all works).
It comes with an SMC Takumar 200/4 lens, which is also very clean inside, the diaphragm, focus ring all very smooth and all the click-stops and stop-down lever, shutter and film advance function well.
One problem: compared to my Gossen Lunasix-3 (and, also, to the Sunny 16 Rule), the TTL lightmeter seem to give/result in readings that (presumably) underexpose to hell ; e.g. for ISO 400 film in bright sun, it suggests about f/22 @ 1/1,000 (a long cry from f/16 @ 1/400? Is this something that could be fixed? (I've been assuming the camera.lens functions in open aperture metering (a la Asahi Pentax Spotmatic SP-F), am I right?)
Thanks in advance for responding.
Second question: I see there are 6x7 SMC Takumar lenses and SMC 67 Pentax lenses: will the Asahi Pentas 6x7 accept the later(?) Pentax 67 lenses or not?
Thanking you in advance for responding.
Comment by Banjo posted on Asahi Pentax 6x7: some questions. at 31/10/2010 - 23:21
alfpics wrote:
I remember reading somewhere that they are happy for you to take photos on the underground so long as you don't use flash (and I guess not a tripod as it could be a lethal trip hazard)
Andy
And -in particular- if you make no attempt whatever- to use your camera or lens! I remember reading somewhere that they are happy for you to take photos on the underground so long as you don't use flash (and I guess not a tripod as it could be a lethal trip hazard)
Andy
Comment by Banjo posted on Taking photos on London Underground? at 29/10/2010 - 01:04
dinneenp wrote:
Hi,
I'll be getting the underground from Heathrow to Knightsbridge and Knightsbridge to Gatwick.
3. Anything else to note?
Cheers,
Pa.
Yes: the paranoia created by relatively recent terrorist activity on the very network of which you you speak.Hi,
I'll be getting the underground from Heathrow to Knightsbridge and Knightsbridge to Gatwick.
3. Anything else to note?
Cheers,
Pa.
On the other hand, it could result in some unintended adventures with enforcers of state security, which could be the basis of numerous entertaining after dinner reminscences?
(Alas, in many ways we are increasingly resembling the post-WWII era of the Soviet Union.)
Comment by Banjo posted on Taking photos on London Underground? at 29/10/2010 - 00:54
[quote:3496ace15f="SmutjeUK...You age, you get wither, I withdrawn my DD instruction to PayPal and may now loose the PayPal account because of this )Clause 10.5 in the new regulations about sellers DD) and with this I stop trading on eBay...
Kind regards
SmutjeUK[/quote]Internet financial transactions are fraught with dangers: literally, you put your finances entirely in the hands of strangers (who may or may not be crooks and, even if they aren't, you are still exposed to hackers or scammers, not to mention dodgy dealers). That's why I would never do it.
Kind regards
SmutjeUK[/quote]Internet financial transactions are fraught with dangers: literally, you put your finances entirely in the hands of strangers (who may or may not be crooks and, even if they aren't, you are still exposed to hackers or scammers, not to mention dodgy dealers). That's why I would never do it.
Comment by Banjo posted on PayPal - be very careful of how you deal with them! at 29/10/2010 - 00:41
There are probably easier ways to kill yourself
Comment by Banjo posted on great mountain climbing pics at 29/10/2010 - 00:25
rickbehl wrote:
Thanks for the responses. I'll try and get out with the camera and tubes in the next day or two to try them out. A couple of thoughts and conclusions on the replies so far...
1) Seems best to use these for close-up/macro type work rather than trying to use them for the 'extra reach' (eg wildlife type images)
2) Looks like general consensus is that the tubes are optimally used with focal lengths in the range of 75-165mm (75mm, 90mm, 105mm, 135mm, 165mm) although of course they can be used practically with all lenses with maybe less than optimal results.
3) I think I get it now with the EC. When the manual says x2.0 it translates to 1 extra stop (ie, double '1' ONE time) and when it says x4.0 it means 2 extra stops (ie, double '1' TWO times). If I summarise the data from the tables in the manual I believe that as a rule of thumb to remember the EC:
Tube #1 (14mm) : Add 0.5 Stop
Tube #2 (28mm) : Add 1 Stop
Tube #3 (56mm) : Add 1.3-1.5 Stops
Again using the TTL meters obviously helps removing the need to remember these numbers.
4) Looks like there should not be too much loss of image quality as long as tubes are used individually and stacking is avoided. Generally it sounds like I should be using very small apertures to get maximum sharpness throughout? As f/22 may introduce softness it sounds like f/13-f/16 is optimum? Also, as noted and probably dictated by these shutter speeds a tripod sounds mandatory.Conversely using a tube with longer lenses should help to produce nice bokeh (probably good for portraits with the 165mm?)
5) A bit confused here. After a couple of tests it looks like the tubes do not allow the aperture modification to be used (pentax service centre mod to display aperture instead of the frame number in the viewfinder display). This is not a big issue really. However just so I am clear on how to measure exposure. It sounds like I cannot use Aperture Priority mode? And I'm not too familar with the term 'stop-down metering' (excuse my lack of knowledge here). Am I right in thinking the procedure for metering with these tubes are:
i) Switch metering mode to manual (ie NOT 'A' mode)
ii) Compose and focus the scene
iii) Set desired aperture for required DOF.
iv) Use the DOF Preview lever to stop down the lens to desired aperture and then set shutter speed to correct exposure (using viewfinder meter to get to Center Mark '0').
v) Press 'Meter Lock' to lock exposure or keep DOF lever locked at stopped down aperture. (However the P67II manual says that the 'ML' button cannot be used when the camera is in Metered Manual Mode?)
vi) Release shutter
Does that sound correct?
Thanks again for all your help!
Rgds
Rick
1) There's no way you would be able to take "distant" images with tubes attached, maybe a face/face and shoulders with a 200mm (35mm equivalent) lens and the shortest tube.Thanks for the responses. I'll try and get out with the camera and tubes in the next day or two to try them out. A couple of thoughts and conclusions on the replies so far...
1) Seems best to use these for close-up/macro type work rather than trying to use them for the 'extra reach' (eg wildlife type images)
2) Looks like general consensus is that the tubes are optimally used with focal lengths in the range of 75-165mm (75mm, 90mm, 105mm, 135mm, 165mm) although of course they can be used practically with all lenses with maybe less than optimal results.
3) I think I get it now with the EC. When the manual says x2.0 it translates to 1 extra stop (ie, double '1' ONE time) and when it says x4.0 it means 2 extra stops (ie, double '1' TWO times). If I summarise the data from the tables in the manual I believe that as a rule of thumb to remember the EC:
Tube #1 (14mm) : Add 0.5 Stop
Tube #2 (28mm) : Add 1 Stop
Tube #3 (56mm) : Add 1.3-1.5 Stops
Again using the TTL meters obviously helps removing the need to remember these numbers.
4) Looks like there should not be too much loss of image quality as long as tubes are used individually and stacking is avoided. Generally it sounds like I should be using very small apertures to get maximum sharpness throughout? As f/22 may introduce softness it sounds like f/13-f/16 is optimum? Also, as noted and probably dictated by these shutter speeds a tripod sounds mandatory.Conversely using a tube with longer lenses should help to produce nice bokeh (probably good for portraits with the 165mm?)
5) A bit confused here. After a couple of tests it looks like the tubes do not allow the aperture modification to be used (pentax service centre mod to display aperture instead of the frame number in the viewfinder display). This is not a big issue really. However just so I am clear on how to measure exposure. It sounds like I cannot use Aperture Priority mode? And I'm not too familar with the term 'stop-down metering' (excuse my lack of knowledge here). Am I right in thinking the procedure for metering with these tubes are:
i) Switch metering mode to manual (ie NOT 'A' mode)
ii) Compose and focus the scene
iii) Set desired aperture for required DOF.
iv) Use the DOF Preview lever to stop down the lens to desired aperture and then set shutter speed to correct exposure (using viewfinder meter to get to Center Mark '0').
v) Press 'Meter Lock' to lock exposure or keep DOF lever locked at stopped down aperture. (However the P67II manual says that the 'ML' button cannot be used when the camera is in Metered Manual Mode?)
vi) Release shutter
Does that sound correct?
Thanks again for all your help!
Rgds
Rick
2) Yes. The use of tubes both reduces the lens' minimum focus distance and prevents the use of infinity focus.
3) You got it.
4) The situation is actually more complicated than that, as the use of tubes actually affects the size of the "effective aperture" (smaller than that indicated on the camera controls). But don't let it bother you, I have often used an indicated aperture of f/22 on 35mm film, and it doesn't show. Also, the number of tubes doesn't so much affect IQ as the available light to work with and all the attendant issues that brings.
If you have "manual" tubes, you can use a hand-held meter and apply the exposure factors you listed in point #3 (above): that should work.
If no hand-held meter, but the light is constant/reliable (e.g. sunny day or 100% cloudy) you can measure your exposure (grey card or substitute reading) with your TTL meter, then mount the tubes, apply the exposure factor, and shoot.
Another way (should work) is to set the camera to Aperture priority Auto Exposure and use the EC control to add exposure according to your exposure factors in #3, above. Focusing is still an issue...but you could pre-focus wide open, using a tripod.
As you can see, manual tubes are "messy" to use. Also, it is very difficult to focus at shooting aperture.
In general, tripods (outdoors) are messy and impractical.
However, using "auto" tubes is relatively simple and fun and easily done hand-held.
Comment by Banjo posted on Extension Tubes at 27/10/2010 - 05:32
BTW there are two types of tube: "auto" and "manual".
The manual tubes require the use of stop-down metering and are best avoided due to inconvenience of use.
The manual tubes require the use of stop-down metering and are best avoided due to inconvenience of use.
Comment by Banjo posted on Extension Tubes at 27/10/2010 - 02:56
I can't answer the lightmeter question, but as the meter is built into the head (not many of the 6x7's I've been looking at recently have had one) you could check if the fault lies within by borrowing another known good example.
Regarding the lenses, yes all vintages of lens will fit and work with all vintages of camera.
I wouldn't use the camera's meter, you'd be better off sticking with your Lunasix.
BTW, the vendor is willing to have the meter recalibrated .
Love the beast: heft, clunky shutter noise, and all!
I guess I'll soon be in the market for two or three more lenses.
Does anyone know anything about the 2x converter (one on offer)? Worth having?:
Thanks for responding.