I use my right eye to look through the view-finder, and suffer a little from this problem too.

Luckily, the K20D diopter adjustments affect me a lot less than did the Sony A200 which I sold recently.

I wear milk-bottle bottoms for specs, but after using the Sony, my right eye became as sharp as a pin for about 15 minutes, whilst my left eye got a lot worse!!!

Alan.

Thanks, John.

Yes, I forgot to mention that when checking the 'info', it showed that centre point metering had been selected, even though the camera was set for matrix metering.

I need to ask about this other point again:

"I have found that the ISO can be easily manually set using the OK button and front wheel together. This is a really handy usable feature. Is this common knowledge, as I've NOT found this feature in the manual...or am I just being dim again?!"

Regards.

Alan.

Reporting back to the forum ...

I did some tests last night with my K20D and Pentax-m 50mm f1.7 lens.

No problems I'm pleased to say!

Stevo/John, I found that the 'in-focus' beep/red-square/green hexagon behaved the same regardless of whether the camera was set to AP-S or AP-C. But it was nice to be fully aware of how these 3 indicators worked.

I found the focusing (on the centre of a flower) to be very sharp (zooming using the camera's screen and roller-wheel) although not always! I'm pretty steady at hand-held phtotgraphy, but I guess at f1.7 even the slightest movement is enough to affect the sharpness.

I did all of this using the camera's M mode of course, which I find is a pleasure to use, especially the top display's indication of light-metering/exposure. Also, using M mode, it's very easy to adjust the shutter-speed and the ISO to suit.

Which brings me on to another point: I have found that the ISO can be easily manually set using the OK button and front wheel together. This is a really handy usable feature. Is this common knowledge, as I've NOT found this feature in the manual...or am I just being dim again?!

Regards to all.

Alan Lowe-Jones.

Thanks, Pete/John.

I should have known that already! Indeed, I have read that in the camera's manual. Doh!

I feel a bit silly now, but in my defence, I'm trying to take in a lot of info at the moment! The good thing is, I'll not forget this little lesson now.

I shall have another play when I get home tonight.

BTW, John, it's Paul Nemeth I work with, not Paul Jones. I think my subconscious had seen Paul Jones on your camera club's website.

Regards.
Alan.

Thanks to all for picking up this thread.

Stevo, I will try 'Trap Focus'; that looks like it could be very useful.
Presently, I've just left the camera on AF-S, although it does beep and give me the red square when, I presume, it thinks it's in focus. I'll try the experiment to see what the difference is.

Shim. Thanks for that link to the review of the Sigma lens. Excellent reading, and I certainly wouldn't be too unhappy now about spending the extra on the Sigma lens.

Changing subjects completely, I followed-up the thread about Jessops selling off stock yesterday, and bought my first flash-gun, the Pentax AF360. I'd been reading the excellent material recently on this forum about flash photography, and had just about made my mind up that I'd go for the AF360 anyway...so it was nice to get it for £121 inc. p&p.

Flash photography, now there's a can-o-worms!

Many thanks to all.

Alan.

Thanks, Pete.

As this appears to have been a 'slow' thread, I gather there aren't too many Sigma 50mm f1.4 owners within the Pentax Forum. Interesting!

Anyway, I very much appreciate your input about your own experience of the auto & manual lenses. It's enough for me to probably delay a while and just keep going with the old manual lens, which btw, I think is excellent.

Have to see what else I can spend my money on!

Cheers.
Alan.

Hi, Pete.
Thanks for replying so quickly.

What I wrote may be misleading, as I'm comfortable with how DOF works, and how it becomes even more shallow (and critical) with increased aperture.

My thread is more to do with the benefits of using autofocus on a lens such as the 50mm f1.4 : is autofocus better than manual at achieving sharpness? We have to assume of course that neither the photographer or the subject moves after focusing.

Also, I guess the autofocus is quicker than manual.

My real question to the forum though is just about the Sigma lens itself, to ask if anyone has experience of using it.

Many thanks.
Alan.

Hello all.

As a newbie and recent recruit to the Pentax fold, I recently bought my first Prime lens, an old Pentax-M 50mm f1.7 from Ebay, in excellent condition. I am now really enjoying the experience of being able to shoot indoors (at this dull time of year) whilst also creating images containing lots of bokeh.

I'm not too upset either at having to manually focus. However, when I roll the rear wheel and zoom in to check for sharpness on the camera's screen, I do notice that I don't always achieve the subject sharpness I'd like. I gather this is not unusual as even tiny head movements (after focusing) can affect this sharpness. I do get lucky sometimes though!

It's therefore possibly time for me to consider buying one of the modern-day equivalents: either the Pentax 50mm f1.4, or the Sigma.

I have to admit that whilst the Sigma is considerably more expensive, it does appear to be a 'better' lens. Perhaps that statement is a tad naïve,
but my question is; does anyone in the forum have experience of using this lens, or indeed, just an informed opinion...unlike myself!

Regards.
Alan Lowe-Jones.

Thank you all, again.

Wonderful advice, which reinforces my own findings, and leaves me to make that big decision some time in the near future. Do I go for the
16-45, the 17-70, or the 16-50?

I undoubtedly have more homework ahead of me yet!

Is there a suspicion that lens manufacturers set out to create these dilemmas in order to extract more money from us, or am I just being overly cynical?!

Many thanks to all.

Alan.

Thanks, hefty1.

That's a brilliant summing-up of these 50mm lenses. My purpose in buying one is to address low-light portrait situations, so the wide-open quality and sharpness at this stop is important to me too.

Many thanks.

Alan Lowe-Jones.