K-r manual focussing



DanielH

Member

Pentax Pro Master 462 posts
3 years
Link Posted 22/02/2012 - 20:52
Im sorry this topic has been covered before in various guises but this is my particular issue.

I cannot focus accurately at wide apertures with the viewfinder. I can with live view however there is a delay of around 0.5 secs between pressing the shutter button and it firing. This isnt great as the subject has usually moved or changed expression! and ive missed it.

1. It looks in focus in the viewfinder and i HAVE adjusted the dioptre in the correct way.

Is there anything i can do?

thanks

Dan


matwhittington

Member

Pentax Pro Master 1,473 posts
5 years
West London, UK
Link Posted 22/02/2012 - 21:02
Dan, I sympathise! I use a magnifying eyepiece on the viewfinder which I think is helpful. I know there are many on here who use a split screen viewfinder, which I think may be even better but may be a bit of a faff to fit...

Cheers
Mat W

My Flickr: link


DanielH

Member

Pentax Pro Master 462 posts
3 years
Link Posted 22/02/2012 - 21:06
Mat do you think its just that i cant see it say below f 2.8 through the viewfinder??
Last Edited by DanielH on 22/02/2012 - 21:06


wvbarnes

Member

Pentax Pro Master 1,041 posts
4 years
Derbyshire
Link Posted 22/02/2012 - 21:17
Hi Dan,

If it's subject moved I guess you are referring to telephoto of wildlife.

I have the KR and when using my 55-300 lens at full telephoto I've found a lot of practice and patience is required BUT the results are worth it.

I use high ISO as the KR sensor can deliver 800 as default 1600 when light low as often the case in winter and still be very good.

I take at around F8 when light allows. Wide open with telephoto makes it very hard!

I use the Shake Reduction hand held. Turn it off when using a tripod. Blurred shots can often be shake not bad focus.

I also use auto focus with centre spot focus and metering for birdlife. The sport mode at six frames a second and costant AF captures my son's speedy Visla dog very well even when she's charging at me!

I get better with time but still envy some of the wildlife photography I've seen.

I'm late fifties with high prescription varifocals. I've found paying out for top lenses for me as helpful as the Pentax kit! The KR has a pentamirror. I'm sure a K5 with a brighter pentaprism would be better. I'm saving up!
Bill
Last Edited by wvbarnes on 22/02/2012 - 21:18


johnriley

Pentax User Team

Pentax User Team 21,071 posts
12 years
Tyldesley, Manchester
Link Posted 22/02/2012 - 21:20
Have you adjusted the dioptre adjustment as per the instructions? That's the usual cause of the problem.

We always use maximum aperture to focus by as lenses are open until they stop down when taking the picture. The wider the maximum aperture, the brighter the image and the easier to see the point of focus. It doesn't end up being more accurate than AF, sometimes less so, unless we spend some time critically getting the point of focus right.

Macro photography in particular can benefit from MF, but anything at a distance is far less critical.

Tests have been made with people focusing, noting the distance on the disatnce scale. Then trying again and noting the distance again actually focused on. The amount of error in our eyes is surprisingly large. AF can be more accurate, especially in lower light.
Best regards, John
Last Edited by johnriley on 22/02/2012 - 21:21


DanielH

Member

Pentax Pro Master 462 posts
3 years
Link Posted 22/02/2012 - 21:26
Bill- yes im saving up to! my only issue is with manual focus as i posted initially and this in low light at shallow dof say f2.8 and wider.

John thanks but as i said yes dioptre has been done. It's a manual lens so i dont have AF as an option. I am pretty accurate 85% of the time with liveview but the shutter lag is killing me!

Probably my only option at this point is to change focus screen


milamber

Member

Pentax Pro Master 862 posts
3 years
Norfolk
Link Posted 22/02/2012 - 21:29
Hi Dan

I have no problems focussing at wide apertures with the viewfinder of my K-r. I regularly use f1.7 and f2.0 with my 50mm and f2.8 with my 135mm. Both of these are manual focus.

There are obviously issues with the depth of field at small apertures so it's always harder to focus, but what I see in the viewfinder is usually what I get. Sometimes the focus is out, but that's due to my error, not the camera - usually optimistically low shutter speeds coupled with low ISO whilst hand held.

Is this focus problem all the time or just sometimes? Presumably you have no problems with the same lens at smaller apertures?

If you are anywhere near Norfolk you would be welcome to try mine and see if it's the camera which has a problem or the lenses you are using.
Last Edited by milamber on 22/02/2012 - 21:33


johnriley

Pentax User Team

Pentax User Team 21,071 posts
12 years
Tyldesley, Manchester
Link Posted 22/02/2012 - 21:29
I find live view quite annoying as it zooms in, locks on and then eventually takes the picture. Except in very rare circumstances, give me the pentaprism every time.
Best regards, John


johnriley

Pentax User Team

Pentax User Team 21,071 posts
12 years
Tyldesley, Manchester
Link Posted 22/02/2012 - 21:31
As an afterthought, if you switch the camera to AF then you can use "catch in focus" so the shutter will only release when the green hexagon lights, indicating the point of focus. It could help you.
Best regards, John


DanielH

Member

Pentax Pro Master 462 posts
3 years
Link Posted 22/02/2012 - 21:39
John Liveview with Manual focus. (AF in viewfinder etc no problem)I havent managed to use catch in succesfully yet.

Milamber thanks, thing is i am not getting what i see in the viewfinder despite careful focussing! I have an old zenit slr and guess what i can manual focus it fine at 1.7! does that mean its something to do with the camera not my eyes?


dcweather

Plus Member

Pentax Pro Master 1,049 posts
5 years
Laindon,Essex
Link Posted 23/02/2012 - 00:00
I've found catch-in-focus remarkably useful at times. It worked surprisingly well on my K-r with a manual 500mm Tamron mirror lens which is fixed at f8.


Infrabasse

Member

Venerable Member 86 posts
2 years
Link Posted 23/02/2012 - 03:41
Seeing this is a K-r, could this be a case of artificial light inaccurate AF?

I had a K-r for a couple weeks before I swapped it for a K-5. I never managed to get a good focus indoors below f/1.8 with my Sigma 50mm f/1.4.
It front focused beyond the focus microadjustment range, but not in daylight.
Last Edited by Infrabasse on 23/02/2012 - 03:55


sterretje

Member

Pentax Pro Master 367 posts
4 years
Roodepoort, South Africa
Link Posted 23/02/2012 - 04:35
dannyh, it's not necessarily you. Your matte screen might not have been shimmed properly in the factory. A split prism screen can significantly help; I use them in both a K10D and a K100D but be aware that they might need shimming.

Another way is to learn to get a feel for the green hexagon; it's a bit tricky as it covers a range. While focusing, focus confirmation will show, but it will still show if you turn it a little further; so there is a range in which the camera thinks it's in focus. The true focus point is somewhere in the middle.

Infrabasse wrote:
Seeing this is a K-r, could this be a case of artificial light inaccurate AF?

Not if one relies on the viewfinder.
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)


milamber

Member

Pentax Pro Master 862 posts
3 years
Norfolk
Link Posted 23/02/2012 - 07:47
Everything suggested might help a little, but with my K-r I don't have this problem with manual focus. I wear glasses, but usually find myself looking over the top of them through the viewfinder, which shouldn't help.

Despite this, I don't have the problem that Dan describes and am fairly confident that 95% of the time what I see in the viewfinder is replicated in the photo - the other 5% is camera shake or trying to focus with very shallow DOF.

Dan shouldn't need catch in focus or to be playing around with the green hexagon. They are valid suggestions for helping to mitigate this, but shouldn't be neccessary. Unless I have a spectacularly good copy of the K-r, which I doubt from the reviews, then there would seem to be an issue with Dan's.

How long have you had it? If it's still in warranty I'd be inclined to return it. Can you try another K-r to see if you still have the problem?

It's certainly not something that you should have to live with. The K-r is a superb camera, but there is always bound to be the odd lemon which slips through quality control.


sterretje

Member

Pentax Pro Master 367 posts
4 years
Roodepoort, South Africa
Link Posted 23/02/2012 - 08:25
milamber wrote:

Despite this, I don't have the problem that Dan describes and am fairly confident that 95% of the time what I see in the viewfinder is replicated in the photo - the other 5% is camera shake or trying to focus with very shallow DOF.

Yep, if you don't need shallow DOF, you will more than likely not have a problem. So yes, you might have an issue with your camera as much as dannyh has if you can not obtain proper focus with shallow DOF.
Pentax K10D + Vivitar 55/2.8 macro + Super Takumar 55/1.8 + SuperMultiCoated Takumar 85/1.8 + SuperMultiCoated Takumar 135/3.5 + SuperMultiCoated Takumar 200/4 + Super Takumar 300/4
Pentax K100D + DA18-55ALII + DA55-300
Pentax K5 + FA31Ltd + M50/1.7 + DFA100WR + M120/2.8 (+ DA18-55WR at occasion)

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