HELP: Why still cannot focus properly (Pentax K-X) ?


guanny

New Member
Aug 26, 2008
104
0
0
www.justinguan.blogspot.com
#1
Hi all,

2 questions to be asked and would appreciate your kind help and advice.


(1)
I previously posted a question on how to correctly focus because my portraits always turn out unfocus (the face).

So the solution I got was to use AF-S mode and 1-point-centre-focus.
I will have to lock the centre focus on the face and then recompose.

But I still have the same problem. My portraits still doesn't stay in focus most of the time (70%).

An example would be:


f/6.3, 1/180, ISO 400 (lowest).


No PP. Just cropped it for easier viewing.

As a result of that, I have to smart sharpen most of my portraits and sometimes, resulting in the photos being 'over-photoshoped'.
I'm quick tired of getting such photos because it is really disappointing and unmotivating. :(

Is there anyone who could give me some advice as to where I had gone wrong? I'm sure it has pretty much nothing to do with the camera.




(2)
Except for the build in flash, I don't own any other flash. And I noticed that when I take outdoor portraits, even when there is adequate light, I will need to overexpose a little so that the face is clear but in doing so, I overexpose the background. And that goes the same vice versa, where the subject gets very shadowed and underexposed if the background looks fine.

I know of people who shoot very well despite not owning a flash so how can I overcome this problem?


THANKS IN ADVANCE FOR YOUR EFFORT IN HELPING OUT :D
 

pinholecam

Moderator
Staff member
Jul 23, 2007
10,950
90
48
#2
Check if you have focus issues.
Do a google for 'how to check for front focus'
here is one :
http://photo.net/learn/focustest/
you can use a rule, newspaper, etc to simulate as well.

BTW, just for clarity, did the model move between the time you focus and recomposed?

Are you shooting in Jpeg or RAW?
RAW will require you to process the files properly (ie. sharpen, etc)
 

guanny

New Member
Aug 26, 2008
104
0
0
www.justinguan.blogspot.com
#3
Check if you have focus issues.
Do a google for 'how to check for front focus'
here is one :
http://photo.net/learn/focustest/
you can use a rule, newspaper, etc to simulate as well.

BTW, just for clarity, did the model move between the time you focus and recomposed?

Are you shooting in Jpeg or RAW?
RAW will require you to process the files properly (ie. sharpen, etc)

Thanks for the reply.
I will check the focus.

Nope, the model didn't move at all. And I'm shooting in Jpg. :think:
 

obfuscate

New Member
Nov 20, 2008
1,524
1
0
#4
Hi all,

(2)
Except for the build in flash, I don't own any other flash. And I noticed that when I take outdoor portraits, even when there is adequate light, I will need to overexpose a little so that the face is clear but in doing so, I overexpose the background. And that goes the same vice versa, where the subject gets very shadowed and underexposed if the background looks fine.

I know of people who shoot very well despite not owning a flash so how can I overcome this problem?


This is a problem regardless of the camera you use. Can you tell us what metering mode you are using? i.e. spot, centre weighted or matrix?
 

titus1984

Senior Member
Jun 15, 2010
1,142
2
38
#5
Hi there

The kx has a slightly different system when it comes to AF because of the lack of focus point illumination. As such you can't see where the camera is focusing. I am a kx user and I have learnt to determine from the view finder if the area I want to focus is where the camera is focusing(by default I am using the auto 11 pt). This is where some people don't like about kx. I guess u got to learn how to go about doing this as times go by.

Personally for me, I will focus on the nose eyes area. If these areas are sharpen upon AF by the camera,most of the time the portrait will be sharp and focus where u want it to be. Also do wait for the SR logo to light up to ensure the anti shake is ready.

Hope it works!
 

Jun 24, 2009
372
0
16
#6
Does this focus problem occur with other subjects? ie inanimate ones of different colours



I had the focus hunting problem, but not the not in sharp focus problem with my KX.
 

#7
let me ask u 1 simple question, if u stick to center focus point, shoot at the face, does it still happen. if it doesn't then its just due to user. U are moving the camera, introducing a shift, if it miss, what do you think ?

u ask question 2 means u dunno wat is exposure... the camera will never know what u are pointing at, the face is just a small part of the pic, of course the camera will expose for the bright background, u want to expose the face, than the background of course will be over... nothing to do with got flash or not... its about understanding the right thing...
 

obfuscate

New Member
Nov 20, 2008
1,524
1
0
#8
u ask question 2 means u dunno wat is exposure... the camera will never know what u are pointing at, the face is just a small part of the pic, of course the camera will expose for the bright background, u want to expose the face, than the background of course will be over... nothing to do with got flash or not... its about understanding the right thing...
I think fill in flash will help leh.
 

Ghostfit

New Member
Jun 17, 2010
1,445
0
0
#10
1) Know that different lense have different characteristics. For zoom lens, most have what is known as a sweet spot, ie: a certain FL where IQ is optimal, this is very evident with some super zooms which are rather soft at their extremes.
Most lense also have a sweet spot with their apertures, they don't perform best wide open and needs to be stopped down.
Try this:
a) Set your lens at the middle of it's zoom range i.e: 50mm with a 35-70mm zoom
b) Using a dry-fit T-shirt on a hangar(or somebody) as subject, focus on the T-Shirt as if shooting a model and capture 5 exposures from wide open aperture to f22, eg: f2.8, f5.6, f8, f11, f22. Study the different IQ of the photos closely (pixel peeping required)
You'll notice that the 'good' apertures settings allows you to resolve the weave material of the dry-fit T-shirt better. ...now you understand a little of the 'limitation' of your gear. :bsmilie:

2) Try to identify 'backlit subjects' and how to use fill flash to correct them.
If you don't care about the BG, then try spot metering on the areas of the subject you want correctly exposed. There is also the option of using the HDR ...but that's a totally different can of worms !:sweatsm:

Good luck and happy shooting !
 

Reportage

Senior Member
Nov 24, 2008
5,785
2
0
#11
i dont use a KX. But you mentioned only 70% of the shots are not in focus so what did you do to get the other 30% in focus?

have you read the memo on page 120 of the KX user manual?

for model shoot, i find recomposing is a tad slow. Try changing the AF point instead or aim dead centre at the subject face and then crop in post.
 

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