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09-05-2010, 03:36 AM   #1
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2 first day issues/questions - KX

Hi all,

After 12 months of research and reading, I finally took the plunge and bought a KX yesterday - it came with an 18-55 and 55-300 lens as part of a twin kit.

Being a typical man, I haven't read the manual yet and have started to play around with it - I have noticed two things which I would really appreciate an opinion on:

1) When I rotate or turn the camera, there is a sensation of something sliding/moving inside the camera. It is more pronounced without a lens attached and it does make a sliding and stopping sound also (as it something is sliding on runners between either side of the camera). It doesn't bother me at all, so long as this is normal - can you provide an explanation or advice?

2) I attached the 55-300 lens last night and tried to focus in on my pet dog at close range and in dim light. I half pressed the button to focus and the camera made one heck of a mechanical/whirring noise and didn't focus - this continued whilst I kept the button half depressed and so I stopped as it clearly wasn't right - any ideas and would I have done any damage?

Thanks very much in advance for your help,

Best Wishes,

FizzBomb

09-05-2010, 04:30 AM   #2
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Issue 1 is normal. The sensor is "Free Floating" because a Pentax has SR (anti shake) and the sensor isn't rigidly fixed to the frame. It moves on a magnetic frame so it can move to compensate for shaky shots. You'll hear a bit of a "clunk" as the sensor shifts inside it's guides as you turn the camera from side to side.

The second situation most likely is nothing. You should try some shots where the subject is further away and in decent light. If the focus locks on properly and just normal screw drive noise, then I suspect everything is fine. The camera was most likely experiencing 2 things. 1) you were inside the minimum focus distance for the lens. Which for this lens is 55.2 inches (1.4m). It can not focus on a subject closer than that and will hunt in trying to lock focus. 2) the light was so low, it also was hunting to achieve focus.

So I think all you heard was the screw drive motor in operation while the camera was trying to lock focus on something it couldn't
09-05-2010, 05:07 AM   #3
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Kx SR mechanism

It's funny, the first day I got my Kx i contacted Pentax because I thought there was something loose in my camera . It's apparantly the SR mechanism.

Welcome to the club!
09-05-2010, 05:11 AM   #4
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Issue #1, 2 - normal behaviour

Regarding issue #2 - there is a certain amount of light reaching the AF sensors that the camera has to use in order to achieve focus. The consumer lenses, especially long zooms, struggle in dim light because added to the dim light there is also their small aperture which lets even less light onto the sensor. Try to use a fast 50mm and you'll see a much better behavior.

Also try to use spot (center) focus and put that center spot onto a contrast line of your subject (for example the eyelid). Using this small trick you'll see AF working better.

09-05-2010, 05:56 AM   #5
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You may have also been too close to Killer (that is what I call all dogs that I don't know).. What Focal length were you trying to grab him at? The behavior you describe would be normal if there's no chance for achieving focus or there is no light (and more specifically, Contrast) to focus On.

09-05-2010, 06:24 AM   #6
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You already received some good advice.

On issue #2: you tried in the evening with low light. The camera might have been unable to focus because of the lack of light in the sensor. The AF focus assist of the K-x is not the best, compared to the K-7.

This shoud disappear during daytime light, or using a faster lens (ie large aperture or smaller f).

Enjoy your camera and show us some shots...
09-06-2010, 11:52 AM   #7
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Thank you

Thanks for the replies all - really helpful and I'm grateful for you taking the time to advise me. Sounds like the only issue is the operators inexperience.

Looking forward to getting to know my KX and sharing some Pics

Cheers

Fizzbomb
09-06-2010, 01:42 PM   #8
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QuoteOriginally posted by hcc Quote
You already received some good advice.

On issue #2: you tried in the evening with low light. The camera might have been unable to focus because of the lack of light in the sensor. The AF focus assist of the K-x is not the best, compared to the K-7.

This shoud disappear during daytime light, or using a faster lens (ie large aperture or smaller f).

Enjoy your camera and show us some shots...
Also, isn't the 55-300 variable aperture?

So for the OP, and if so, if you focus at 55 using center point focus, you're focusing at the widest aperture the lens can give you, which might be enough for AF (autofocus) to properly operate in low light. Once you have that confirmation, you can zoom in for the shot you want.

I also want to also make sure thet the OP is aware that the K-x has different focus point settings, and this can make a big difference in low light situations as well. And this a reason so many of us stick to center. For a lot of scenes, the camera doesn't know "what" to focus on, if it's not set to center.

If we're shooting a cat sitting on a piano, all we care about is getting the cat in focus as our starting and main focus point, as opposed to shooting the Coliseum in Rome.

09-06-2010, 01:51 PM   #9
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Silly question I am sure - but what is OP?

What would the best setting be to stick to whilst I am in my 'green' phase?

Thanks again for the help,

Fizzbomb
09-06-2010, 03:03 PM   #10
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I think it stands for Original Poster, not sure though
09-06-2010, 04:09 PM   #11
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QuoteOriginally posted by agsy Quote
I think it stands for Original Poster
Yep:

There are a ton of acronyms on this site for photography which makes it difficult to absorb everything at first for newbies, but OP is one that's used on every site that you visit.
09-06-2010, 04:20 PM   #12
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QuoteOriginally posted by fizzbomb Quote

What would the best setting be to stick to whilst I am in my 'green' phase?
Always a hard question to answer:

I suggest for exposure settings, you have manual ISO settings. So if you're outdoors in bright soon, you have it fixed at 100 or 200. If it gets shady, go to 400. Indoors, 800 to 1200.

If you use auto ISO, you don't know when it's changing, and why.

And with fixed ISO, you use Av mode, aperture priority mode, where you choose the aperture (which affects your depth of field) and the camera automatically selects your shutter speed. You wouldn't use this to shoot horses at the race track, but as you begin to learn shooting static, non-moving subjects, this is the best way to understand the relationship between ISO, aperture, and shutter speed:

It's these three things together that are interrelated for correct exposure.

Use a less sensitive ISO of 100 at F4, and switch it to more sensitive of ISO 200, and your aperture has to be twice as small, going to 5.6, to get the same correct exposure. And yeah:

F stops don't change exponentially. F2.8 lets in twice the light of F4. F4 lets in twice the light of F5.6. F5.6 twice the light of F8. F8 twice the light of F11. F11 twice the light of F16. F16 twice the light of F22.

It'll all sink in in time, so don't get a headache about it just yet.
09-06-2010, 08:46 PM   #13
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QuoteOriginally posted by fizzbomb Quote
Silly question I am sure - but what is OP?

What would the best setting be to stick to whilst I am in my 'green' phase?
Until you understand a setting and what it's for and why you'd want to change it, you might as well just leave everything at the defaults. Do a camera reset (in the setup menu, probably) to return there if you've been messing iwth stuff you might not remember how to put back. Leave the main dial on Auto. As soon as you learn what exposure compensation is - the first control you need to understand on any camera - switch to P mode and leave it there until you've got a reason to put it elsewhere.
09-06-2010, 10:28 PM   #14
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QuoteOriginally posted by Ira Quote
Also, isn't the 55-300 variable aperture?

So for the OP, and if so, if you focus at 55 using center point focus, you're focusing at the widest aperture the lens can give you, which might be enough for AF (autofocus) to properly operate in low light. Once you have that confirmation, you can zoom in for the shot you want.
.
The 55-300 is not a parafocal lens, which means unfortunately that this technique won't work.
09-07-2010, 03:40 PM   #15
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QuoteOriginally posted by fizzbomb Quote
Hi all,

After 12 months of research and reading, I finally took the plunge and bought a KX yesterday - it came with an 18-55 and 55-300 lens as part of a twin kit.

Being a typical man, I haven't read the manual yet and have started to play around with it - I have noticed two things which I would really appreciate an opinion on:

1) When I rotate or turn the camera, there is a sensation of something sliding/moving inside the camera. It is more pronounced without a lens attached and it does make a sliding and stopping sound also (as it something is sliding on runners between either side of the camera). It doesn't bother me at all, so long as this is normal - can you provide an explanation or advice?

2) I attached the 55-300 lens last night and tried to focus in on my pet dog at close range and in dim light. I half pressed the button to focus and the camera made one heck of a mechanical/whirring noise and didn't focus - this continued whilst I kept the button half depressed and so I stopped as it clearly wasn't right - any ideas and would I have done any damage?

Thanks very much in advance for your help,

Best Wishes,

FizzBomb
I used to be the same way, I wanted to figure it out on my own. But now I read it cover to cover.

I got my Kx a couple of weeks ago and it helped me to also go through all the menus and options of each; if this is your first DSLR, you will be amazed at everything it will do.
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