[rawr]

I must say after taking the Pentax K-5 out the first time this weekend, I was a little disappointed. My first shot turned out very blurry.

Practice, practice, practice. Walk about with the camera and your lens during the day, during the night, get to know it better.

My NEX-5 involved a learning curve too. I hated it initially, but now I am comfortable with the ways of NEX (the Sigma 30mm helped). The K-5 is capable of performing wonderfully if you just get to know it better.

[Dr_who]

Are you taking your pictures auto or are you in Av mode or Sv mode ect. I rarely see iso go up to 3200 unless in a fairly dark area. Maybe try Av mode and put the aperture at 2.8-4.5 ish.

[Xiong]

Are you taking your pictures auto or are you in Av mode or Sv mode ect. I rarely see iso go up to 3200 unless in a fairly dark area. Maybe try Av mode and put the aperture at 2.8-4.5 ish.

It was shot in Tav mode. 2.8 1/25 shutter and auto iso was set to 3200. In full manual mode, auto focus wouldn't even lock.

[rawr]

1/25 shutter

That is a very slow shutter speed for hand-held. Your blurry picture problem is most likely related to that.

In full manual mode, auto focus wouldn't even lock.

??? 'Full manual mode' would normally mean you are manually focussing, and have the camera mode dial set to M.

TAv isn't fully manual, just quasi manual because while you may be in control of aperture and shutter in TAv, ISO is still being adjusted by the camera according to the program line. And of course your AF settings (AF-S, AF-C, MF) and AF pattern (11/5/spot etc) are controlled outside of your exposure mode.

[Xiong]

I'll have to post pictures later, but it was either lower shutter speeds or grainy high ISo pictures. Nex-5n to my surprise took the shot without any hesitation.

After doing some research it looks like the focusing issue of the 50-135 is a known problem. A bit disappointing that a brand new lens that cost as much as it does, was having issues auto focusing.

[GnipGnop]

Most of the time, the problem is with the the thing behind the camera, not in front of it.

Here's the best advice I've read to help with autofocus. It's from a Pentax rep and it's when everyone should do when they first get their camera.

Take off your lens, and look through the viewfinder at fairly bright light source. Adjust the diopter until the lines in the viewfinder are perfectly focused.

Seems simple, but helps a great deal. Don't be so quick to judge your equipment. You have given us no information to go on to help you. How dark was it when you were doing this? What were you focusing on, a black cat on a pile of coal or something with more contrast? Did you wait for the SR to activate? How good is your technique when shooting a dSLR with a OVF compared to a NEX5 that you hold out in front of you?

...or it could be the lens. Probably not though.

[Xiong]

I had to manually focus the lens, because it would not lock and take the picture - the lens would not auto-focus if my life depended on it. (Auto-Focus seems to be functioning the way it should now - which I am relieved). Here's what I was trying to focus on and I know a prime lens will do better in this light situation, but my original complaint was that the 50-135 would not auto-focus.

Pentax (with 50-135) 1/50 at f/2.8 ISO 6400


Sony (with Sigma 30mm) 1/30 at f/2.8 ISO 3200

[GnipGnop]

Why don't you taking your camera out and shooting things you actually want to take pictures of and see how it performs? Or are you content with taking pictures of handrails? Sorry to sound sharp, but get out and use your camera, and then come back and tell us how it worked.

Take photos of a dark piece of wood at ISO 6400 is not relevant to anyone in judging autofocus abilities.

[Xiong]

Gnipgnop, do you own a 50-135?

[felixkh]

Test your camera and lenses in real world situations to see if it is the camera or the lens. GnipGnop is right. Shooting a silly piece of wood in the dark at ISO6400 is not an ideal test of your equipment

[Xiong]

I know everyone is just trying to be helpful, but it doesn't sound like everyone is reading all my post. It sounds like you guys are very quick to come to the rescue of the Pentax camera. If you guys read my post, I stated that I took it out over the weekend and found my first shot to be blurry. I took it home and did some test on it (the super awesome subject that I bought my camera for - haha) and found that the autofocus would hunt back and forth and not even lock focus. The reason why I ask if he owns a 50-135, is because he might be aware of the issue of the lens. I am by no means a pro, but I think I found my reason why it would not autofocus:

Q: Our survey found that the Pentax DA* 16-50mm and 50-135mm were the most prone to SDM failure. Do you know why this was?
A: One could say that the AF components used in these lenses was prone to failure from the get-go due to their design. The 16-50mm and 50-135mm lenses share the same circuitry and motor, which is why they both have such a high failure rate. Other SDM lenses don't fail as much.

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/207986-new-50-...-bad-copy.html

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/112834-da-50-1...e-pattern.html

[felixkh]

I know everyone is just trying to be helpful, but it doesn't sound like everyone is reading all my post. It sounds like you guys are very quick to come to the rescue of the Pentax camera. If you guys read my post, I stated that I took it out over the weekend and found my first shot to be blurry. I took it home and did some test on it (the super awesome subject that I bought my camera for - haha) and found that the autofocus would hunt back and forth and not even lock focus. The reason why I ask if he owns a 50-135, is because he might be aware of the issue of the lens. I am by no means a pro, but I think I found my reason why it would not autofocus:




https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/207986-new-50...-bad-copy.html

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/112834-da-50-...e-pattern.html

If you bought yours new recently, then the issues would have been solved by now as Pentax has changed the motor for the lenses.

[felixkh]

I must say after taking the Pentax K-5 out the first time this weekend, I was a little disappointed. My first shot turned out very blurry.

Today my 50-135 was not able to focus on an item 5 feet away. After changing a few of the AF settings, changing lens to MF back to AF. Turning it off/on a few times, some how it started focusing again. Whew. But this still doesn't sit we'll with me as I don't know if this focus thing will become a bigger issue later on.

My sony nex-5n was able to focus and take a better picture at lower ISO. The pentax while was on auto ISO was constantly at 3200+ and the exposure still looked very dark.

Let's do a check:
1. Where is your AF point? Centre or off centre.
2. Is the subject in line with the AF point?

[Ash]

Auto ISO is a customisable setting as well. By your own admission, if ISO was constantly high and your results were dark, then there was simply insufficient light to get a decent result from your exposure settings. If you want things to be manually set, go to M mode. AF on the 50-135 is by SDM technology, which on this particular lens is reasonably reliable. If you are convinced there is a problem with the lens, you should just return it. Or you can reexamine your technique and see if it's all functioning well in real world photography. Remember also that focus points are quite large and the camera requires adequate contrast to accurately nail the focus. There are a number of other factors involved, but these are just some of the main issues that may be leading to the problems indicated here. More information is definitely needed, but even then, it will not be easy to demonstrate compositional and focusing technique via the Internet.

[Xiong]

The lens is back to normal - no more of that autofocus hunting (under same light and settings).