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07-23-2019, 09:47 PM   #1
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K50 Focusing questions ??

I have a K50 I purchased used off a person that I ask why he was selling such a low shutter count less than a couple months old. They told me that the camera was a gift and he felt the camera didn't take as sharp of pictures as his Nikon.. The camera does once in a while take really sharp pictures just not most of the time.. It seems the auto focus system is wracked out,, the auto focus seems to hunt when it gets close to focus , it states it's in focus the red block in the viewfinder, yet it seems like it's decided that the focus can be better and you can hear it doing little steps with the lens , while it's doing this the red block locks and unlocks in the same place,, sometimes it just gives up and focus to one end , I'm not sure if it's one end or the other ,, I think it's ether , yet have not confirmed.. I need to go back and check yet it seems that I remember getting pissed because even though I had set it to fire the shutter even if un-focus yet it steps so much so quickly most times it will not let the shutter fire, the shutter override could just be operator error ,, I seem to member some settings in the settings menu were related to shutter override..

I have done a reset when I first had the aperture problem , I don't think I did one after the recent firmware upgrade.. During my looking for info. on the aperture I saw a K70 going for cheap because the person that was selling it got it for free with the person given it to him stated that the only issue it had was "It doesn't take sharp pictures." the person selling it figured out it had the aperture issue and didn't want to put the time or money into,, I thought great somebody else with the same issues I have with my K50 yet they had noted that they were never able to get properly exposed pictures with it,, so the sharpness issue was never confirmed...

It's been stated that maybe this dust or dirt in the AF path,, Which is what I'm hoping it is.. So my question(S) are pointed at those who know or have worked on the mechanical workings of the K50 AF system..

1. Were is the AF sensor located , how big is it (Posted picture would be nice..).
2. Is it adjustable , can it be knocked out of adjustment without damaging some other more fragile items (Like bumping the camera without leaving a mark..) , is it possible that it didn't get adjusted correctly at the factory ??
3. I don't notice anything odd when I look thru the viewfinder , yet is it possible that the mirror is tilted or not returning to the correct location ??

Lastly I was going to start a new post asking about focusing screens , yet I had my Super Program focusing screen changed to flat matt because I hated the focusing aids.. So I think I'll stay with the focusing screen that the K50 has.. So here's the question , I always thought focusing screens are made of glass, so what is a resin focusing screen ?? Are they ant better ??

TIA
DEM

07-23-2019, 10:19 PM - 1 Like   #2
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Try using AF-S (single shot drive mode) and focus in live view in good light so that you can use a fast shutter speed and ensure shake reduction is on. If you are able to get sharp shots this way but not when focussing via the optical viewfinder then it's possible that you need to carry out AF fine adjustment for the lens.
It's also possible that there is dust etc on the AF sensor, which you can attempt to clean using a rocket blower. Set the camera for mirror up sensor cleaning, with the lens off, hold the camera so the lens mount is pointing down and use a few blast of the rocket blower aimed at the AF sensor in the base of the camera.
Post a test shot or two so we can get a better idea of what your images look like, and ensure exif data is intact.

Cheers,
Terry
07-24-2019, 07:54 AM   #3
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This is the typical AF behavior of the K-50 along with similar cameras like the K-30, K-500, & the original K-5. The AF will lock at times with great results, but I find it that is misses focus about +-30% of the time. The viewfinder will tell you that the subject is in focus, but once you see the image, it's off. Mind you that I have my camera set up with back button focus & I've even done the "lens adjustments" in the camera. The AF module in these older cameras pretty much sucks. I have to focus manually quite often. Even the fast focusing DA 55-300mm PLM can get confused on the K-50. Shooting in dim light makes everything even worse.

If you want a bit more accurate & better autofocus, you'll need to step up to a K-5II or K-5IIs. The K-S2 & K-70 have the same AF module that the K-5II/IIs has. The K-3 is a bit more accurate & the K-3II took it a step further. The KP might be a hair better than the K-3II, but the AF is basically the same. But even then, once you use a Nikon, Canon, or other cameras from different manufacturers, you'll start to understand why a lot of reviewers slam Pentax for their lack of AF performance.

I'm comparing a large orange to an apple here, but I use a Nikon D7200 when I need to get very accurate focusing. The downside of that is the lack of IBIS for low light shooting. I'll need to raise the shutter speed & ISO to get reasonable shots when I can't lug a tripod. Heck, even the old mid-range Nikon D5200 that belongs to my niece has far better AF than the K-50. It even has a very basic 3D tracking. It's not as good as the 3D tracking in the D7200, but it can certainly do way better than the K-50. Don't get me wrong, I do enjoy shooting my K-50, but the AF can be very frustrating at times. I'm currently waiting for that upcoming Pentax APS-C flagship with hopes of it finally having similar or better AF performance than the Nikon D7200 or even the D7500. I'll be thrilled with that alone.

So yeah. Only one of 2 things will happen to you. You're either going to get very frustrated with the K-50 or you're going to get very good at manual focusing. Hahahaha! I suggest you try setting up your camera with back button focus & using the lens adjustments in the camera. Try using some of these settings too. You'll either need to buy a lens adjusting kit or print a lens focusing sheet online. You have to follow directions carefully to get the best results. There is no other type of adjustment available in the camera. But yeah. It's not going to be much of a difference with a K-50. Ultimately, if you want more reliable AF, you'll need to step up to a higher or newer Pentax model or switch brands.
07-24-2019, 10:05 AM   #4
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thanks tduell:
I'll try that this weekend.

I'm a little confused on the AF system , did I read that the AF system is done differently in LV mode than it is in VF mode ??

I'm thinking / hoping that everybody right and there's dirt or dust someplace, I don't think it's a finger print.. It appeared that after I replaced the aperture solenoid it got clearer, yet I'm sure the solenoid replacement did not have any effect on on the focusing unless I knocked some dust off someplace. I've never cleaned inside the shutter box or mirror of any camera with the exception of my super program I got a fat greasy thumb print on it..

Bad habits: Early on I was taught not clean inside the shutter box unless it really needed it and only clean lenses when this an issue and lightly at that (film cameras). I used to look inside the shutter box once in a while with my film cameras.. About the time I went DSLR I had stopped looking in the shutter boxes unless I saw something on the mirror , which maybe was once or twice. I never thought about if dust gets on the film it goes with the film to the processor, yet on a DSLR any dust stays in the camera so it's probably best to check inside the shutter box.. I know better yet I have a habit of removing the lens from the K50 to use on another body and I leave the camera face up with no body cover. It's not that I don't have body covers ,, I've just gotten lazy !!!

Wish me luck I'm going to look in the mirror box and see if there's dust, dirt, finger print..

One last question , what would be the effect if any of getting a finger (thumb) print on the underside of the mirror ??

TIA
DEM

07-24-2019, 11:26 AM   #5
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The Squirrel Mafia: Off subject I thought the KP was the flagship ??

Frustrated to put things lightly.. Manual focusing I was pretty good at it with my SP..

I'd be a little less frustrated if I could figure out the setting will let the shutter fire without it being in focus , I thought I found it , yet I seem to remember it wouldn't fire even set so the shutter should fire un-focused,, as I stated it seems to get in this hunting mode it's in focus yet it's taking little steps around the focus point and will not fire.. I'll need to check again.. My K20 I don't ever remember it hunting for focus lock, sometimes it would do the end to end thing and give up.. The K-01 , I'm sure it's done the end to end thing one of twice and most times as soon as it has focus lock it fires. Once in a great while it seems to have an issue what to focus on , the red box will jump locations most times it hunts once or twice locks and fires , sometimes the item that you're shooting will be out of focus and the item that the red box stopped on will be in focus {This normal operation !!) .. I wish I could spell the way it sounds when hunting (very tiny steps), looking thru the viewfinder it don't look like the focus is changing, it's the sound , blinking box and the shutter not firing , that sets this body off from my other Pentaxs. It does it even in the brightest light sunlight much less and forget low light most times it just goes end to end and gives up.. I know both the K-01 and the K20 give up sometimes in low light it seems to be less , now that I'm trying to think this thru, yet I can't be sure I shoot more with the K50 than the K-01 so it could just be I notice more on the K-50.. The K20 not designed to be as good in low light as the K50 or K-01..

Sorry for the long one just trying to piece together , what I'm looking for over the weekend.. It's so odd there has to be something in the focus path.. seems to me I saw someplace a drawing on the focus path somewhere.. If somebody knows a link for it ,, please share..

Being Lazy, going to post it here instead of above. I figure out what the K50 hunting sounds like "Moss code" !!

Thanks
Dave
07-24-2019, 11:47 AM   #6
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"I'm a little confused on the AF system , did I read that the AF system is done differently in LV mode than it is in VF mode ??"

When using the Live View function, the camera uses contrast detection autofocus from the sensor data. When using the OVF, the traditional phase detect AF is used.

---------- Post added 07-24-2019 at 11:50 AM ----------

FWIW I've generally found the single AF on the K50 and KP to be reasonably decisive, if lacking in intelligent detection. So I don't recognize the particular behavior you describe.

The AF-C and contrast detect, on the other hand, is pretty shaky on both. I never bother with AF-C.
07-24-2019, 11:50 AM   #7
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QuoteOriginally posted by dem5867 Quote
I'd be a little less frustrated if I could figure out the setting will let the shutter fire without it being in focus
It's the menu C2 12. & 13. set them both to option 2, release priority and FPS (Frames Per Second).

I don't recall having such issues with my K-50, I thought that tduell's advice was on the money. Please post an image so that we can advise further?
07-24-2019, 02:36 PM   #8
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QuoteOriginally posted by dem5867 Quote
The Squirrel Mafia: Off subject I thought the KP was the flagship ??
Long story short, it was probably supposed to be the K-3II replacement when it first came out, but then Ricoh quickly stated that it wasn't the APS-C flagship. My guess is that the backlash from the Pentax community probably forced them to rethink their APS-C flagship strategy. The specifications of the KP ended up being more of a downgrade when compared to the specifications of the K-3II. While the KP excelled in some things like IQ & 5-axis IBIS, it did worse in a lot of other things. Hopefully the K-3II replacement arrives sometime next year with much better AF. I've been waiting for it since the fall of 2016............

07-24-2019, 05:31 PM   #9
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QuoteOriginally posted by dem5867 Quote
The Squirrel Mafia: Off subject I thought the KP was the flagship ??
The flagship's the 645Z. Then there's the K-1. Then there's the KP for APS-C. But the KP is not a K-3 replacement, that's till to come.
07-26-2019, 11:18 AM   #10
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Wow , There's clearly 2 schools of thinking when it comes to mirror cleaning,, Some say do it and others clearly say don't touch it. I was told many years ago by a big camera shop don't clean the mirror !! My personal experience I cleaned a 35mm mirror with damp lens paper and scratched it, I couldn't see it thru the viewfinder. Lens paper just never made sense to me, dry it's really hard and to make it soft one has to wet it damp just don't work, I was showed to fold it so it's ~2" * 2" and just damping it to clean lenses, yet I scratched a lens with the one of the folded corners..

I was hoping and kind of itchy to clean the K50 this weekend , I'm amassed how many people state there AF works so much better and I found a Pentax user on another forum that seemed like very close to the same issue I have, he found a piece of hair laying across the AF sensor..

I decided to order new supplies the supplies I have for cameras is old and well the lens paper that I scratched a lens with.. I have a couple of puffer blowers , I just don't trust them so I ordered a Rocket Blower.. I have electronic and lab grade cleaning swabs and cloths , yet the dust free cloths have treads that come off the sides, they are dustless just not thread-less. I ordered sensor cleaning swabs, cleaner for sensors and new lens cloths 4" * 4".. Can anybody think of a must buy item(s) that I don't have listed ?

I know not to use canned air,, I read something that just seemed like such a bad idea,, somebody talked about using a standard (Tire) air compressor , lucky somebody told him only use a low pressure oil-less compressor , I have both low pressure / low volume medical compressors (Like fish tank air compressors yet have both in and out ports. I don' even think there 5psi open ended.) and medium mid volume \ pressure maybe 7 psi open ended , I wouldn't use them for cleaning a camera , that just seems like asking for issues.. I was surprised there seemed to be some people that seem to be really aggressive when cleaning cameras !! I was taught don't clean the shutter box unless there's an issue (Film), I guess today's DSLRs require a cleaning schedule. Yearly ??

Lens brushes ? I has a couple of older giveaway free be brushes, I've never used them, another item I was told not to.. I saw a couple of users use lens brushes in the shutter box, one person used a carbon ion brush to attack dust without touching anything.. Comments ?

Last question, the ion brush got me thinking what about a ion generator ?? I know your all thinking are you crazy, If have a couple of dc and ac ion generators, yet I'm not talking about those (Which I would be afraid of damaging something.) , how about the hand powered gun type ??

TIA

Last edited by dem5867; 07-26-2019 at 11:23 AM.
07-26-2019, 12:42 PM   #11
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To clarify: the red block in the vf only indicates which focus point is in use. To simplify your troubleshooting, try selecting the center point only. Then watch for the green hexagon AF indicator in the viewfinder. It will glow steadily when focus is achieved. If it's blinking, the subject is not in focus.
07-28-2019, 04:45 AM   #12
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The AF Sensor is located under the mirror:
http://img.photobucket.com/albums/v313/RiceHigh/Web%20Linking/cnPentax/K100DS_AF_Module.jpg

It is pretty straight forward but sucking air out is better than blowing air in.

For this you can use a vacuum-cleaner which can be set for low suction. You need some kind of extension for a smaller tube.
Now you have to built an antistatic protector which can easely be done with a single cable, one end is on the earth terminal of the mains plug, the other end stripped for about 5 cm.
The bare thin copper wires to inside the tube and remain there. You fix this cable with tape to the tube and now you have the possibility to suck air out without any danger of electrostatic problems.

There are ESD vacuum cleaners, but DIYers did it long time ago for computers:
Grounding a vacuum cleaner | Tom's Hardware Forum

There is nothing wrong in cleaning the mirror! Of course anything that can scratch it...

With finest microfiber cloth such as for glasses it works perfect but they have to be cleaned as well.


Canned air: Depends on which one, in Europe we have Ballistol which works very well.

Air Duster with 80 liter spray volume.

It is particular for sensitive electronic equipment and digital cameras.
But one has to work first a bit with it, get used to it, understand it.... and maybe waste some of it.... better than to produce hot air....
07-28-2019, 08:39 AM   #13
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Thanks ,, I never thought about the green hexagon, I now the red box was the focus point, it seems to me I read in one of the manuals the when the red box is lit solid the cameras in focus lock , maybe that's not true anymore (Could had been from a manual for from one for the 1st Pentax AF cameras.) ?? I used to use the green hexagon , I think I stopped, when I read about the red box or maybe I just started to see what the focus point is / was because of the issue.. The green hexagon makes sense, getting old wish I could member when I started using the red box for focus lock, It could have been with the K50, funny when I was playing with the K20 I noticed it , maybe it didn't come on very often or maybe I was trying to figure out why it appeared to quickly get to the focus point and start doing the di-di-di-di thing trying to find focus lock !!

I need to clean my equipment.


QuoteOriginally posted by paulh Quote
To clarify: the red block in the vf only indicates which focus point is in use. To simplify your troubleshooting, try selecting the center point only. Then watch for the green hexagon AF indicator in the viewfinder. It will glow steadily when focus is achieved. If it's blinking, the subject is not in focus.
07-28-2019, 09:45 AM   #14
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photogem: I'm still having issue with the quoting thing I can't figure out how to just quote sections, I tried highlighting the item I want quoted yet it appears to copy the whole post.. Anyhow I'm going to try to keep it short (As you already know I'm not known for short..)..

Canned Air; I remember years ago when canned air was made with Freon the cans stated that (Dust-Off brand.) it was specially design for using on cameras ,,etc. Yet not that I read every can , I read a lot because I would love to if cans that don't say "Do not use on sensitive items like camera mirrors and coated lenses. Yes I was once told by a mechanic when I went to him with a caliper issue that the manual in big bold letters said "Do not use air .." well he used a few pounds of air, so I asked him "But the manual stated use no air,," he looked at me and said "I never read the manual I just know how to do it !!" On a job site I did see somebody cleaning an instrument with front coated mirrors, lenses and other fine optics with canned air , I asked him about the warning he stated that as long as you used it carefully and made sure you kept the can at right angle not to let any of the liquid come out it's fine. I know my limitations and spray cans are one of them, if you need something screwed up with a spray can send it to me , paint , lubes, glue, etc.

Bulb blowers , I never thought of using them in vacuum mode like one does with a de-soldering bulb.

There are ESD vacuum cleaners, but DIYers did it long time ago for computers:.
I have 2 service vacuums I believe one for them is ESD proof, yet I presently can not get to them, in lue of them I have a battery powered keyboard vacuum that just might fit the need..

With finest microfiber cloth such as for glasses it works perfect but they have to be cleaned as well.
I ordered the some of the highest rated from Amazon.. As I stated above I have a few really high end lab instrument lint free cloths yet they leave 1" or larger threads all over the place !!

Thanks everybody for all the fantastic tips.. I'm getting itchy to clean my cameras, yet I have to wait until my supplies come in.

Lens brush, yes / no ??

QuoteOriginally posted by photogem Quote
The AF Sensor is located under the mirror:
http://img.photobucket.com/albums/v313/RiceHigh/Web%20Linking/cnPentax/K100DS_AF_Module.jpg

It is pretty straight forward but sucking air out is better than blowing air in.

For this you can use a vacuum-cleaner which can be set for low suction. You need some kind of extension for a smaller tube.
Now you have to built an antistatic protector which can easely be done with a single cable, one end is on the earth terminal of the mains plug, the other end stripped for about 5 cm.
The bare thin copper wires to inside the tube and remain there. You fix this cable with tape to the tube and now you have the possibility to suck air out without any danger of electrostatic problems.

There are ESD vacuum cleaners, but DIYers did it long time ago for computers:
Grounding a vacuum cleaner | Tom's Hardware Forum

There is nothing wrong in cleaning the mirror! Of course anything that can scratch it...

With finest microfiber cloth such as for glasses it works perfect but they have to be cleaned as well.


Canned air: Depends on which one, in Europe we have Ballistol which works very well.

Air Duster with 80 liter spray volume.

It is particular for sensitive electronic equipment and digital cameras.
But one has to work first a bit with it, get used to it, understand it.... and maybe waste some of it.... better than to produce hot air....

Last edited by dem5867; 07-28-2019 at 03:37 PM.
07-29-2019, 01:01 AM   #15
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QuoteOriginally posted by dem5867 Quote
photogem: I'm still having issue with the quoting thing I can't figure out how to just quote sections, I tried highlighting the item I want quoted yet it appears to copy the whole post.
Here you can see how it looks like when I quote your post:



Then later you can learn who to insert a previous quote into a new quote. It is actually pretty easy and straigthforward as well.


QuoteOriginally posted by dem5867 Quote
Anyhow I'm going to try to keep it short (As you already know I'm not known for short..)
That sounds a bit like an excuse and then doing it again?

It is simply by leaving the unnecessary out.


Example: Canned air and freon: There is no need to mention freon because freon is banned since 1987 as well as other CFC's.

Plus all those endless stories following up... no need.

You have specific questions. Just try to keep them short and clear.

Then: Apply given advice and write about success or failure.

(again if you can... short and precise, leave all those flowers, garlands, excursion/detours etc. out because you want precise and clear advice)


For example: You got hints about cleaning the AF Sensor.
About a sound which beebs when focus locked (plus the green hexagon AF indicator).

If you look at your past posts, you might see that you started all this in a strange complicted way.
You wrote about the solenoid, the K20D and trying to fix it with a green solenoid and how bad the K50 is.

You put the cart before the horse.

It would have saved you (and us) a lot of those complicated detours if you just would have asked:

"I can't get sharp pics with my K-50, am I doing something wrong or is it my K-50?"

Very simple actually.
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