Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
11-06-2009, 03:00 AM   #1
New Member




Join Date: Jan 2008
Location: england
Posts: 14
Program Line

With my K10 the Program line has 4 settings one of which is MTF. This program prioritizes the best aperture settings for the attached lens. Can anyone tell me if this only works with Pentax lenses, or will it also work with non Pentax lenses ?

11-06-2009, 05:19 AM   #2
Loyal Site Supporter




Join Date: Mar 2009
Location: Southern Indiana
Photos: Gallery
Posts: 14,956
I believe that it will work for any lens that has an 'A' setting for the aperture.
11-06-2009, 05:31 AM   #3
Inactive Account




Join Date: Oct 2008
Location: Rochester, NY
Photos: Gallery | Albums
Posts: 119
I think the MTF line only works with the more modern pentax 'chipped' lenses or AF lenses - I'm not 100% sure. I would imagine the only way the camera can determine the sharpest performance on a lens, especially a zoom, at a given focal length would be to somehow embed an MTF chart data when coupling with the camera.

I have tried this with a A50 1.7 and it would try to set aperture to f/22 which I know shouldn't be the MTF program line value. Not sure how if it works with a 3rd party lens.
11-06-2009, 05:53 AM   #4
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
According to the K20D manual, it works with DA, D FA, FA, and FA J lenses.

I was disappointed with the MTF mode selection for my DA 18-250. I was shooting at 18mm and it chose f4. Maybe that is the optimum point for sharpness, but the vignetting is ugly. They should not have specified that aperture, especially since f5.6 is as sharp and does not vignette like that.

I'm mostly using P-MTF as a reference. I may check what the MTF mode says for the lens, then I go back to Av and set what I want. I've had some bad results due to the camera sticking resolutely to the MTF aperture and compromising badly on shutter speed and/or ISO.

11-06-2009, 10:01 AM   #5
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by audiobomber Quote
According to the K20D manual, it works with DA, D FA, FA, and FA J lenses.

I was disappointed with the MTF mode selection for my DA 18-250. I was shooting at 18mm and it chose f4. Maybe that is the optimum point for sharpness, but the vignetting is ugly. They should not have specified that aperture, especially since f5.6 is as sharp and does not vignette like that.

I'm mostly using P-MTF as a reference. I may check what the MTF mode says for the lens, then I go back to Av and set what I want. I've had some bad results due to the camera sticking resolutely to the MTF aperture and compromising badly on shutter speed and/or ISO.
The MTF program is strictly about the "sharpest" aperture. As such, it isn't going to be compromised by any other factors, since if it is, it is no longer an MTF program.
It's up to the user to ensure that the program line in use is appropriate to the lens/conditions, especially as this is considered an advanced user feature for educated users.
11-06-2009, 10:53 AM   #6
Pentaxian
Ratmagiclady's Avatar

Join Date: Nov 2008
Location: GA
Photos: Gallery | Albums
Posts: 13,464
I really like the MTF program line, myself: combined with the Hyperprogram feature, it really gets me close to the SS/aperture I'd want to pick, anyway, and it's easy to shift around from there, which is a boon for someone who's used to mechanical dials and rings on the lens: with which I've usually got my exposure set by the time the camera's fully to eye, and meter just to get it down to the stop or half-stop I usually want.

I commonly leave the camera in P mode whenever he goes back in the bag, or while wandering around, just to be quicker in whatever situation might next arise. While shopping, I always liked the hyperprogram/hypermanual way of being set up, but I honestly didn't think I'd use it this much. The MTF line is a favorite little feature of mine for this.

I'll agree it's maybe most useful for those who know what they're about: and it really doesn't hurt to have really good handholding skills (I'm pretty obsessive about how things feel, and being someone who prefers lower light and portrait length lenses, I count myself quite good. If you give me the SR and no film being wasted, I'm not alarmed at all if the shutter speed gets down around 1/20 of a second. You have to watch things like subject motion, though. (And for me, overconfidence) SR and such can't help you there.

But it's a good tool. Does sensible things. (I believe that a lot of third-party lenses will interact with this program, or at least a 'generic' profile of lenses of that focal length. ) I just got an old Sigma zoom and have noted the program line has a distinct bias toward wanting to give me f 6.7. Which does seem like a good aperture. The EXIF seems to know what this lens is, but I don't know where the MTF info comes from.

I'd take audiobomber's caution, though, and be aware of your own limits and actual results if you use this program line. Easy enough to override. Mileage may vary, of course: it 'thinks' enough like me that I like it. If you're disagreeing all the time, well, use another one.
11-06-2009, 11:29 AM   #7
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by Wheatfield Quote
The MTF program is strictly about the "sharpest" aperture. As such, it isn't going to be compromised by any other factors, since if it is, it is no longer an MTF program.
It's up to the user to ensure that the program line in use is appropriate to the lens/conditions, especially as this is considered an advanced user feature for educated users.
I don't know if it's quite that straightforward. I just tried my FA 50mm on MTF priority. Lighting didn't affect the aperture selection. It used f2.0 at close focus and f5.0 at infinity. In between it went in-between. I find it hard to believe that f2.0 is the sharpest aperture at minimum focus, but maybe I'm wrong. At any rate, a setting like f4 at 18mm on an 18-250 seems to me to be a poor compromise. Going a stop wider wouldn't drop the sharpness, may increase it, and wouldn't vignette so badly. The programmer should have considered that, IMHO.

As far as MTF being an advanced user feature, since when is P mode only for advanced users? If MTF won't compromise on sharpness, should Hi-Speed compromise on shutter speed? Using your reasoning it would end up at 1/4000s all the time, even if it has to go to maximum aperture, ISO 6400. Program mode is supposed to use good rules of photography for when I don't necessarily want to. In P-MTF mode, the program shouldn't choose a shutter speed that can't be handheld or a high-noise ISO. Since the program doesn't heed good rules of photography, I cannot use P-MTF as a default mode. I still value it, but it's not as useful as it could be.
11-06-2009, 11:39 AM   #8
Pentaxian
audiobomber's Avatar

Join Date: May 2008
Location: Sudbury, Ontario
Photos: Albums
Posts: 6,631
QuoteOriginally posted by Ratmagiclady Quote
I commonly leave the camera in P mode whenever he goes back in the bag, or while wandering around, just to be quicker in whatever situation might next arise. While shopping, I always liked the hyperprogram/hypermanual way of being set up, but I honestly didn't think I'd use it this much. The MTF line is a favorite little feature of mine for this.
My default mode is User, set for Program, but I have to remember not to leave P-mode on MTF. It's a shame that User selects the current Program mode instead of being able to store its own. The great thing about User is that I can change any parameter, and then reset to my known baseline just by turning off the camera.

11-06-2009, 12:36 PM   #9
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by audiobomber Quote
I don't know if it's quite that straightforward. I just tried my FA 50mm on MTF priority. Lighting didn't affect the aperture selection. It used f2.0 at close focus and f5.0 at infinity. In between it went in-between. I find it hard to believe that f2.0 is the sharpest aperture at minimum focus, but maybe I'm wrong. At any rate, a setting like f4 at 18mm on an 18-250 seems to me to be a poor compromise. Going a stop wider wouldn't drop the sharpness, may increase it, and wouldn't vignette so badly. The programmer should have considered that, IMHO.

As far as MTF being an advanced user feature, since when is P mode only for advanced users? If MTF won't compromise on sharpness, should Hi-Speed compromise on shutter speed? Using your reasoning it would end up at 1/4000s all the time, even if it has to go to maximum aperture, ISO 6400. Program mode is supposed to use good rules of photography for when I don't necessarily want to. In P-MTF mode, the program shouldn't choose a shutter speed that can't be handheld or a high-noise ISO. Since the program doesn't heed good rules of photography, I cannot use P-MTF as a default mode. I still value it, but it's not as useful as it could be.
Why not? By choosing MTF, you are telling the camera to use what is programmed into it as the "best" aperture for that particular lens.
It's up to the user to adhere to goods rules of photography, not the camera. When you choose a paticular exposure mode, it is up to you to ensure that it is appropriate, especially if you take the camera off of the green PHD mode and into one of the other exposure modes.
If the MTF program line isn't working because of your failure to know your equipment and it's limitations, or because you are refusing to follow good photographic practices, then that is on you. All the manufacturer can do is give you a piece of equipment that works in a predictable fashion so that you can base your user decisions appropriately.
I don't often use program mode so I can't really speak to how it works in practice, but I would expect a high speed program to choose a high enough shutter speed to stop action, but certainly a speed based at least on the 1/FL rule, and the depth of field program to choose an aperture based on the hyperfocal distance.
If it isn't doing this or something similar, then it is broken software.
11-06-2009, 12:37 PM   #10
Pentaxian
Wheatfield's Avatar

Join Date: Apr 2008
Location: The wheatfields of Canada
Posts: 10,043
QuoteOriginally posted by audiobomber Quote
My default mode is User, set for Program, but I have to remember not to leave P-mode on MTF. It's a shame that User selects the current Program mode instead of being able to store its own. The great thing about User is that I can change any parameter, and then reset to my known baseline just by turning off the camera.
The user mode is, as far as I am concerned, broken.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, lenses, line, pentax, pentax help, photography, program, settings
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
k-x: setting the program line preference anthonyl Troubleshooting and Beginner Help 4 01-13-2010 01:58 PM
'Normal' program line on K10D? J2R Pentax DSLR Discussion 11 05-28-2009 09:59 PM
Custom Setting - Program line ivanp Pentax DSLR Discussion 3 05-07-2008 11:59 AM
What's your Program Line set to? deludel Pentax DSLR Discussion 10 04-06-2008 01:03 AM
Selectable program line Trub Pentax DSLR Discussion 9 09-03-2007 02:20 AM



All times are GMT -7. The time now is 01:42 PM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top