RE: Macro question
I sometimes take a pad of 1.5 x 2 inch post-it notes into the field. Just tear off the bottom sheet and put the whole pad over the finder. When it stops sticking, tear off another and keep going... Or - shoot in manual mode (then the light leakage has no effect.) - MCC At 09:54 AM 7/29/2002 -0400, you wrote: >Ok, >I feel a bit stupid. There is a long story that leads to the solution that >I won't bore you with, but the long and short is that I was not using (and >didn't know I should be using) a viewfinder cover when taking these shots. >Light leakage into the viewfinder was causing the underexposure. - Problem >solved. >Note to self - use viewfinder cover if eyeball not in viewfinder. >J > >-Original Message- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] >Sent: Friday, July 26, 2002 10:01 PM >To: [EMAIL PROTECTED] >Subject: Re: Macro question > > >Jason, >I'm using automatic, not manual on the Super Program with Bellows. >For manual, you will need to stop the lens down to do the metering. >Otherwise, you have been taking pictures at open aperture. >Regards, Bob S. > >[EMAIL PROTECTED] writes: > ><< Bob, > Hey, those are some nice CRISP pics! (and correctly exposed!!;-) ) > Did you take those using the manual mode on the camera setting the exposure > based on what the camera said in the viewfinder or some other method. > When I do what you suggest the double cable release operates correctly, and > use the camera's internal metering, all shots are underexposed 2 to 3 >stops. > Jason > > -Original Message- > Jason, > > Sorry for misreading. Without a flash, using the Super Program and a >bellows > works like this for me... I have an autobellows A. The bellows shutter > release plugs into the camera and the front of the bellows (lens end). > Depress the plunger slowly and you will see that it closes down the >aperture > on the lens before it fires the shutter. This way, the camera/lens is used > > at open aperture, but the aperture is closed down to shooting aperture and > the scene metered before the shutter is released. > > It's worked for me, but then I haven't used over 1 to 1 very often. See > these... > http://pug.komkon.org/00marc/tulipb.html > http://pug.komkon.org/02feb/grape.html > Regards, Bob S. >> >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . - - - - - - - - - - Mark Cassino Kalamazoo, MI [EMAIL PROTECTED] - - - - - - - - - - Photos: http://www.markcassino.com - - - - - - - - - - - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question
> This is why the LX ;-) makes such a great macro camera. The OTF > meter makes viewfinder blinds superfluous. Add to that TTL flash > and various prisms and you have a great system. I just recieved > a Super Program and have not had time to try it out yet. Should > make some interesting comparisons to the LX. Of course, your new SP will also have the TTL flash (and DOF preview) like the LX ;-) and will also make a good macro rig, too, but don't forget that viewfinder blind for the SP... . Fred - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question
On Monday 29 July 2002 09:54, Vick, Jason wrote: > Ok, > I feel a bit stupid. There is a long story that leads to the solution that > I won't bore you with, but the long and short is that I was not using (and > didn't know I should be using) a viewfinder cover when taking these shots. > Light leakage into the viewfinder was causing the underexposure. - > Problem solved. > Note to self - use viewfinder cover if eyeball not in viewfinder. > J > This is why the LX ;-) makes such a great macro camera. The OTF meter makes viewfinder blinds superfluous. Add to that TTL flash and various prisms and you have a great system. I just recieved a Super Program and have not had time to try it out yet. Should make some interesting comparisons to the LX. Christian - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question
Jason, Yes, a viewfinder cover is a good idea too. I've had the same problem, but it didn't occur to mention it. Regards, Bob S. [EMAIL PROTECTED] writes: > Ok, > I feel a bit stupid. There is a long story that leads to the solution that > I won't bore you with, but the long and short is that I was not using (and > didn't know I should be using) a viewfinder cover when taking these shots. > Light leakage into the viewfinder was causing the underexposure. - Problem > solved. > Note to self - use viewfinder cover if eyeball not in > viewfinder. > J - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question
Jason, I'm using automatic, not manual on the Super Program with Bellows. For manual, you will need to stop the lens down to do the metering. Otherwise, you have been taking pictures at open aperture. Regards, Bob S. [EMAIL PROTECTED] writes: << Bob, Hey, those are some nice CRISP pics! (and correctly exposed!!;-) ) Did you take those using the manual mode on the camera setting the exposure based on what the camera said in the viewfinder or some other method. When I do what you suggest the double cable release operates correctly, and use the camera's internal metering, all shots are underexposed 2 to 3 stops. Jason -Original Message- Jason, Sorry for misreading. Without a flash, using the Super Program and a bellows works like this for me... I have an autobellows A. The bellows shutter release plugs into the camera and the front of the bellows (lens end). Depress the plunger slowly and you will see that it closes down the aperture on the lens before it fires the shutter. This way, the camera/lens is used at open aperture, but the aperture is closed down to shooting aperture and the scene metered before the shutter is released. It's worked for me, but then I haven't used over 1 to 1 very often. See these... http://pug.komkon.org/00marc/tulipb.html http://pug.komkon.org/02feb/grape.html Regards, Bob S. >> - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question
Hi, > Does anyone know how the camera's (MZ-S and Super Program) > on-board metering works when there is no communication between > the camera and the lens? Yes. Look at http://kmp.bdimitrov.de/extras/K-mount/K.html > Specifically, I am using the auto bellows and a 100mm macro lens > and am consistently getting underexposed negatives. I generally > find +2 to +3 stops of compensation is required to get correct > exposure. It sounds like you are using a "manual" bellows, and are closing down the lens 2-3 stops. But if the bellows does not have an automatica-aperture coupler, the camera does not know that the lens will stop dow 2-3 stops. Now, if you were using an LX or a flash, it would work. Otherwise you need to overexpose by so many stops as you are closing the lens from its widest aperture. Good luck, Boz - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
> Is it accurate to conclude that the slower the lens, the flatter > focusing field? The 50/4 is flatter than the 50/2 is flatter than > the 50/1.7, et cetera? Well, I imagine that your generalization is probably true most of the time, within a group of otherwise similar lenses. I would suspect that, say, in the A 50's, the field of the f/2 might be slightly flatter than that of the f/1.7, which in turn is almost certainly flatter than that of the f/1.4, with the field of the f/1.2 very possibly showing the most curvature. (Just a hunch...) However, the M 50/4 Macro does not have a flatter field primarily because it is a slower lens (although that may be a contributing factor) - it has a flatter field because it was specifically designed as a ~macro~ lens (i.e., a lens which has to focus close, of course, but which also should be able to render a flat plane of focus properly. (Just another hunch...) However, I wouldn't be surprised if both the newer A 50/2.8 Macro and the even newer F/FA 50/2.8 Macro have an even flatter field, despite being faster than the f/4. (And still another hunch...) Fred - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
Timothy Sherburne wrote: >Thanks to Peter, Ayash, Kevin and Fred for their responses, which all came >to basically the same conclusion: the A50/1.4 simply does not have a flat >enough field of focus to work well for macro photography; the curvature of >the lens elements are becoming more apparent as the depth of field >decreases. > >Okay, with that said, I believe the solution was to use a slower lens or >stop down. Is it accurate to conclude that the slower the lens, the flatter >focusing field? The 50/4 is flatter than the 50/2 is flatter than the >50/1.7, et cetera? I've been told by knowledgable folks on this list that the 50/1.7 is a bit better in this regard but flatness of field isn't *related* to max aperture so the 50/2.0 isn't necessarily better. Of course, an actual macro lens will be best of all, whether it's a 50/4.0 or 50/2.8 or whatever. -- Mark Roberts www.robertstech.com - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
RE: Macro question...
I dunno about that. I always thought that a flat field of focus was what I needed to do copy work of flat pictures and documents. I really thought that flat field of focus was not necessarily an advantage when doing macros of 3-D objects. I would advise shooting at smaller apertures to attain greater DOF. To do that, you may need to use faster film, or get a ringlight to get more light to allow using smaller apertures. Len --- -Original Message- From: Timothy Sherburne [mailto:[EMAIL PROTECTED]] Sent: Thursday, January 24, 2002 12:14 PM To: Pentax Discussion List Subject: Re: Macro question... Hello again! Thanks to Peter, Ayash, Kevin and Fred for their responses, which all came to basically the same conclusion: the A50/1.4 simply does not have a flat enough field of focus to work well for macro photography; the curvature of the lens elements are becoming more apparent as the depth of field decreases. Okay, with that said, I believe the solution was to use a slower lens or stop down. Is it accurate to conclude that the slower the lens, the flatter focusing field? The 50/4 is flatter than the 50/2 is flatter than the 50/1.7, et cetera? t - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
Hello again! Thanks to Peter, Ayash, Kevin and Fred for their responses, which all came to basically the same conclusion: the A50/1.4 simply does not have a flat enough field of focus to work well for macro photography; the curvature of the lens elements are becoming more apparent as the depth of field decreases. Okay, with that said, I believe the solution was to use a slower lens or stop down. Is it accurate to conclude that the slower the lens, the flatter focusing field? The 50/4 is flatter than the 50/2 is flatter than the 50/1.7, et cetera? t On 1/23/02 10:16 PM, Timothy Sherburne wrote: > Hello all... > > I've got a question regarding macro photography. First, some background. > I've been experimenting with three different techniques for increasing > magnification: using a M50/4 Macro, a set of Vivitar auto extension tubes, > and a Vivitar Macro Focusing 2x TC. I use a A50/1.4 with the tubes and TC. > My target magnification is 1/2x (1:2) and my subject is a flat document (a > 10 DM note, to be precise). I've placed a sheet of float glass over the top > of the note to ensure flatness. Film varies with whatever happens to be in > my ZX-M at the moment. Aperture for these tests is always f8. The camera is > tripod mounted and I've done my best to make sure the front lens element is > parallel to the subject. > > Now for the question: I get good results with the M50/4 Macro and great > results with the Vivitar TC + A50/1.4, but something strange is happening > with the tubes. I'm using the 20mm tube with the A50/1.4 to get ~1/2x > (actually 0.4x) and I cannot get the subject entirely into focus! When the > center is in focus, the corners are soft and when the corners are in focus, > the center is soft. I can stop down to f22 and use the DOF preview and > everything looks good, but that really isn't a fair comparison with the > other setups, is it. I don't see the same problem using the other equipment. > > So what is it about the tubes? Are there some obscure laws of physics at > work here? > > t > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
My comment. Nice job. At 07:37 PM 1/24/2002 +1100, you wrote: > > Actually there's no obscure laws of physics here. Most general purpose > > lenses do not have a truly flat field of focus. This doesn't matter much > > when you're working at normal distances where depth of field and the fact > > that most objects are three dimensional tend to obscure that fact. > >I am just playing with macro now with a P30n and a bellows with a 50mm 2.8 >This is a result showing a narrow Depth Of Field, my goal here (other than >to >stop the frog from bouncing away) was to get the eyes in focus. >http://www.photocritique.com.au/modules/photocritique/ShowImage.php?ImageID= >21 > >Kind regards >Kevin >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
Actually there's no obscure laws of physics here. Most general purpose lenses do not have a truly flat field of focus. This doesn't matter much when you're working at normal distances where depth of field and the fact that most objects are three dimensional tend to obscure that fact. When you are working at macro distances depth of field becomes so narrow that the curvature in the plane of focus becomes an issue. You can possibly eliminate this problem by stopping down to f11 ~ f22. The macro is designed to give a much flatter plane of focus so you shouldn't see quite so pronounced an effect. The only effect the tubes are having is to allow you to focus to a much closer distance than normal. At 10:16 PM 1/23/2002 -0800, you wrote: >Hello all... > >I've got a question regarding macro photography. First, some background. >I've been experimenting with three different techniques for increasing >magnification: using a M50/4 Macro, a set of Vivitar auto extension tubes, >and a Vivitar Macro Focusing 2x TC. I use a A50/1.4 with the tubes and TC. >My target magnification is 1/2x (1:2) and my subject is a flat document (a >10 DM note, to be precise). I've placed a sheet of float glass over the top >of the note to ensure flatness. Film varies with whatever happens to be in >my ZX-M at the moment. Aperture for these tests is always f8. The camera is >tripod mounted and I've done my best to make sure the front lens element is >parallel to the subject. > >Now for the question: I get good results with the M50/4 Macro and great >results with the Vivitar TC + A50/1.4, but something strange is happening >with the tubes. I'm using the 20mm tube with the A50/1.4 to get ~1/2x >(actually 0.4x) and I cannot get the subject entirely into focus! When the >center is in focus, the corners are soft and when the corners are in focus, >the center is soft. I can stop down to f22 and use the DOF preview and >everything looks good, but that really isn't a fair comparison with the >other setups, is it. I don't see the same problem using the other equipment. > >So what is it about the tubes? Are there some obscure laws of physics at >work here? > >t >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Macro question...
Hallo Timothy! The focussing plane of a non-macro lens is not flat, it is spherical (if spherical glass elementsa are used). Therefore, if you keep the center at focus,the corner will go out of focus and if you keep the corner in focus, the center will go out of focus, in general. Our eyes can not see that happening because the radius of 'circle of confusion' which creates the image is much smaller than the resolution of our eye. However, Stopping down increases the depth of field and you got good results at f/8 with the TC on. Now, when you are using the extension tubes, the depth of field is affected more. How much?? Well, the answer to this question is a nomogram that I have scanned from a book on Macro photography which gives the depth of field when a certain length of extension is added to the 50 mm focal length lens. I can not send that nomogram as an attachment file as most of the pdml members will object. Therefore, I shall send you only in a separate mail. Hope this helps. Cheers, Ayash. On Wed, 23 Jan 2002, Timothy Sherburne wrote: > Hello all... > Now for the question: I get good results with the M50/4 Macro and great > results with the Vivitar TC + A50/1.4, but something strange is happening > with the tubes. I'm using the 20mm tube with the A50/1.4 to get ~1/2x > (actually 0.4x) and I cannot get the subject entirely into focus! When the > center is in focus, the corners are soft and when the corners are in focus, > the center is soft. I can stop down to f22 and use the DOF preview and > everything looks good, but that really isn't a fair comparison with the > other setups, is it. I don't see the same problem using the other equipment. > > So what is it about the tubes? Are there some obscure laws of physics at > work here? > > t > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
