Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-11-2011, 09:24 AM   #31
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by JohnBee Quote
However... a few days ago, I realized that using the AF indicator with a MF lens proved to be off. Way off in fact...
I got my K-5 in on Friday and shot many shots with it over the weekend and I also have the same problem. I updated the firmware to the latest last night hoping that it will solve the problem, it did not.

I shoot a lot with MF lenses so I noticed it immediately. To confirm, I tripod'd the K-5 and shot some detailed items with my MF 50 1.7, then mounted the K-X with the same lens on the tripod at the same exact position and snapped the pic - the K-5 was not only off, but way off, not even close (pic was shot when red focus box/point confirmed).

The focus indicator (not the red focus box, but the green indicator) seems to be more open k-5, meaning when turning the focus ring, once the subject is in focus, there is a ton of play with the focus (turning focus ring left and right) before the k-5 actually says it is out of focus, this is not the case with my k-x.

Could this be a bad copy of the k-5?

04-11-2011, 12:01 PM   #32
Veteran Member




Join Date: Dec 2009
Location: Deep Forest
Posts: 630
AF system detects a hard contrast line in the AF point region, either vertical, horizontal, or both.

It sounds like the AF system turns the focus motor, detects a hard line, continues to turn focus motor until the hard line is lost, then backs up the focus motor half-way between where detection first occurred and where detection was lost.

If that is how it works, then with MF lens, focus from infinity to find where the focus point turns on, continue turning focus ring slowly just until focus point turns off, then set ring half-way in-between. The catch-in-focus feature cannot be used that way, unfortunately. Useless for MF lens?

For MF lenses I use my eyes and the viewfinder. The unlit focus points are distracting, the flashing ones annoying. Those get in the way because the viewfinder shows so much more than what is in focus...a very different style from using AF. There are techniques for using MF for fast action; AF there can be much easier!
04-11-2011, 05:49 PM   #33
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
QuoteOriginally posted by Wheatfield Quote
You obviously are too used to making false presumptions.
I do own and use a 50/1.2 and several f/1.4 lenses and use them regularly. I'm not buying into what you are saying, since to my eye it isn't true. I can focus perfectly accurately at f/1.2, and can see DOF differences between f/1.2 and f/1.8. Whether it is perceptually the same as on the image or not doesn't matter a whit.
Depth of field is a factor of the lens, not the focusing screen. I've heard that urban legend before, I thought it was horsepoo when I heard it, and I think it is horsepoo now, even though it has moved from urban legend to accepted but false fact.
LOL - love your posts Wheatfield (and I don't mean that in a sarcastic way - you just have a way with words that I enjoy reading!)

I think there may be some truth based on those micro lens on the focusing screen though ...

I get the feeling what I am looking at is slightly deeper than what I am capturing, especially if I capture below f2 on my FA43/1.9 and A50/1.7 - wouldn't be able to quantify it though ...
04-11-2011, 06:09 PM   #34
Veteran Member
joe.penn's Avatar

Join Date: Mar 2011
Location: Maryland (Right Outside Washington DC)
Photos: Gallery | Albums
Posts: 2,902
QuoteOriginally posted by rhodopsin Quote
If that is how it works, then with MF lens, focus from infinity to find where the focus point turns on, continue turning focus ring slowly just until focus point turns off, then set ring half-way in-between. The catch-in-focus feature cannot be used that way, unfortunately. Useless for MF lens?
rhodopsin, I tried what you typed (quoted above), and I ran into something interesting. While backing down the focus from infinity to get the shot into focus, the "focused indicator (green)" would beep in, as it should when the subject is in focus - this is the weird thing, as soon as it beeped in, I would start slowly turning the focus back up (back to infinity), it would take almost a 1/4 turn of the focus ring before the focus indicator would go back off to indicate "out of focus", but i could clearly see that the subject was clearly out of focus long before the indicator indicated it.

Using 50mm 1.7, center focusing while doing this test. Does this not sound odd? The camera exhibited this behavior every time I tried this...

04-11-2011, 08:00 PM   #35
Veteran Member




Join Date: Jan 2009
Location: Fredericton New Brunswick Canada
Photos: Albums
Posts: 332
QuoteOriginally posted by Wheatfield Quote
. . . I've heard that urban legend before, I thought it was horsepoo when I heard it, and I think it is horsepoo now, even though it has moved from urban legend to accepted but false fact.
So Smeggypants's pants are full of horseypoo too? Ewwwwww.
04-11-2011, 08:54 PM   #36
Veteran Member
Christine Tham's Avatar

Join Date: Nov 2008
Location: Sydney, Australia
Photos: Gallery
Posts: 2,269
QuoteOriginally posted by Wheatfield Quote
Are you telling me you actually expect to see a big difference in DOF between f/2 and f/1.9?
No, I was suggesting that the apparent DOF through the viewfinder seems to be a lot deeper than the the lens aperture would imply.

Not f2 vs f1.9 but f1.9 vs dunno f4 maybe ...

I am not using the stock screen, but a Katz Eye with Optibrite, so I'm suspecting that Optibrite may increase the apparent depth of field.

I'm not speaking based on facts, just wild speculation so it may indeed be fantasy.

Edit - for clarification, I don't have an issue with using the split prism or the microprism ring on the Katz Eye either. My comment was more on the apparent depth of field of the rest of the screen vs the results when I actually take a picture.

Last edited by Christine Tham; 04-11-2011 at 09:00 PM.
04-11-2011, 09:00 PM   #37
Veteran Member
Chex's Avatar

Join Date: Feb 2011
Location: The 'Stoke, British Columbia
Photos: Gallery
Posts: 1,700
QuoteOriginally posted by Wheatfield Quote
I use a screen with a split image AND a microprism collar. I have no problem making one or the other work. This is how it has been for decades in my world.
For the purpose of ceding points here, I do admit that the stock screen is not the best for manual focus, but for me, this implies that the screen should be changed to something that works, and nothing more.
Pentax needs to hire your for common sense.. and you can run their PR department

I longingly wait for my income tax returns for my Katz-eye purchase, this viewfinder screen that comes with the K-5 is something I would expect on a point and shoot or old instamatic.. not a DSLR.
04-11-2011, 11:44 PM   #38
Pentaxian




Join Date: Apr 2007
Location: Sweden
Posts: 1,883
QuoteOriginally posted by Wheatfield Quote

I use a screen with a split image AND a microprism collar.
Ok, I thought we where talking about Pentax focusing screen.

04-12-2011, 04:07 AM   #39
Loyal Site Supporter




Join Date: Sep 2006
Location: Bronx NY
Photos: Gallery | Albums
Posts: 5,599
QuoteOriginally posted by Christine Tham Quote
No, I was suggesting that the apparent DOF through the viewfinder seems to be a lot deeper than the the lens aperture would imply.

Not f2 vs f1.9 but f1.9 vs dunno f4 maybe ...

I am not using the stock screen, but a Katz Eye with Optibrite, so I'm suspecting that Optibrite may increase the apparent depth of field.

I'm not speaking based on facts, just wild speculation so it may indeed be fantasy.

Edit - for clarification, I don't have an issue with using the split prism or the microprism ring on the Katz Eye either. My comment was more on the apparent depth of field of the rest of the screen vs the results when I actually take a picture.
Christine, I have to agree with you. I can't speak for the K-5, but I have owned/own DS, K10D, K20D and K-x. on all of those cameras, the apparent DOF in the viewfinder has been/is wider than the actual DOF as captured by the sensor. IIRC, this was true of my ZX-5N film camera as well. This has been commented on multiple times in these forums if not elsewhere. I had thought this was common knowledge, but obviously not. That is not to say I can't focus precisely, but just that you have to be careful with wide apertures.

NaCl(what you see may not be exactly what you get)H2O
04-12-2011, 07:14 AM   #40
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by Wheatfield Quote
You obviously are too used to making false presumptions.
I do own and use a 50/1.2 and several f/1.4 lenses and use them regularly. I'm not buying into what you are saying, since to my eye it isn't true. I can focus perfectly accurately at f/1.2, and can see DOF differences between f/1.2 and f/1.8. Whether it is perceptually the same as on the image or not doesn't matter a whit.
Depth of field is a factor of the lens, not the focusing screen. I've heard that urban legend before, I thought it was horsepoo when I heard it, and I think it is horsepoo now, even though it has moved from urban legend to accepted but false fact.

Well I'd check again if I were you.

1] Put your 1.2 lens on your camera and focus on something

2] Then note how out of focus stuff is in front and behind the focal point is

3] Take the picture

4] then look at the picture and note how much more out of focus the stuff is in front and behind the focal point.

You're buying the wrong brand of Horsepoo because I have shown this effect to several photographers and all of them saw it.
04-12-2011, 07:15 AM   #41
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by Chex Quote
Pentax needs to hire your for common sense.. and you can run their PR department
Canon and Nikon would love that.
04-12-2011, 07:20 AM   #42
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by Christine Tham Quote
No, I was suggesting that the apparent DOF through the viewfinder seems to be a lot deeper than the the lens aperture would imply.

Not f2 vs f1.9 but f1.9 vs dunno f4 maybe ...

I am not using the stock screen, but a Katz Eye with Optibrite, so I'm suspecting that Optibrite may increase the apparent depth of field.

I'm not speaking based on facts, just wild speculation so it may indeed be fantasy.

Edit - for clarification, I don't have an issue with using the split prism or the microprism ring on the Katz Eye either. My comment was more on the apparent depth of field of the rest of the screen vs the results when I actually take a picture.
Yes this is correct. Despite the false claim by Wheatfield that it's horsepoo, it's a proven fact. It's simple to prove for anyone who actually owns a wide lens
04-12-2011, 07:24 AM   #43
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by joe.penn Quote
I got my K-5 in on Friday and shot many shots with it over the weekend and I also have the same problem. I updated the firmware to the latest last night hoping that it will solve the problem, it did not.

I shoot a lot with MF lenses so I noticed it immediately. To confirm, I tripod'd the K-5 and shot some detailed items with my MF 50 1.7, then mounted the K-X with the same lens on the tripod at the same exact position and snapped the pic - the K-5 was not only off, but way off, not even close (pic was shot when red focus box/point confirmed).

The focus indicator (not the red focus box, but the green indicator) seems to be more open k-5, meaning when turning the focus ring, once the subject is in focus, there is a ton of play with the focus (turning focus ring left and right) before the k-5 actually says it is out of focus, this is not the case with my k-x.

Could this be a bad copy of the k-5?
Possibly. I had to exchange my first K-5 becuase the AF was focussing way way to forward in low light.

However I have some MF lenses which are way out of focus in any light levels when the AF Confirm says 'Yes!" on all Pentax DSLRs I have owned
04-12-2011, 07:27 AM   #44
Site Supporter
aliasant's Avatar

Join Date: Feb 2010
Location: Stockholm
Photos: Gallery | Albums
Posts: 634
Just got my replacement K5 and its spotfree AND.
For me even more important.

No more Front Focusing issues so far!

Draw your own conclusions...

Smeggypants and others affected.
Maybe try and see if you can get your FFing K5 replaced?
04-12-2011, 07:29 AM   #45
Veteran Member
Smeggypants's Avatar

Join Date: Sep 2010
Posts: 1,536
QuoteOriginally posted by aliasant Quote
Just got my replacement K5 and its spotfree AND.
For me even more important.

No more Front Focusing issues so far!

Draw your own conclusions...

Smeggypants and others affected.
Maybe try and see if you can get your FFing K5 replaced?
Yup did that a month ago.
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!
af, camera, dslr, focus, indicator, k-5, k-5 ii, k-5 iis, k5, lens, mf, pentax k-5
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
M42 adapter for pentax mount with focus confirm? zoe Pentax SLR Lens Discussion 6 03-24-2013 09:35 AM
DA* 16-50: AF confirm issues at infinity nicolas1970i Pentax SLR Lens Discussion 2 12-27-2010 02:56 AM
Does the K-X have manual focus confirm with ...... dude163 Pentax SLR Lens Discussion 13 05-22-2010 02:46 PM
Confirm mount. Simon23 Pentax SLR Lens Discussion 4 06-09-2009 03:15 PM
Can someone confirm that there is a sigma 100-300 hsm F4 Torphoto Pentax SLR Lens Discussion 8 05-06-2008 08:13 AM



All times are GMT -7. The time now is 02:21 AM. | 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