Attempt at manual focus etc.

Waiting for my computer backups to finish, so decided to "have a go" with the Pentax-A 50mm f1.7, subject is a bit iffy (light pull in our study)

[IMG]http://i941.photobucket.com/albums/ad254/weldingblues/Lightpull.jpg[/IMG]

C & C please

Thanks

The focus looks a bit more on the wall and a little less on the pull to my eyes, don't you think?

Best wishes, K.

I tend to agree Kris.

Colin was it you that mentioned you were interested in getting a Katz Eye split prism focus screen?
It would help no end in just this sort of circumstance.

Yes, the pull is out of focus but the wall spot on.

Keep trying Colin, manual focusing takes a lot of effort to get right, but once you get the hang it's well worth it.

A Katz Eye screen would help if you intend doing a lot of manual stuff( note to self must get one some time!).

Hi Womble, Greytop & Hardgravity,
I agree with the comments regarding focus, I will get a Katz Eye screen at some stage this year.

But will also have another go (differant subject) ASAP.

Thanks for the comments

Regards

Doubtless a different screen will help with manual focus, but there's still no reason why AF confirmation shouldn't enable you to focus manually, and have the camera tell you it's in focus.

Using the green confirmation hexagon in the viewfinder works fine for subjects like this. You just need to be sure it's using the centre AF point, and, very importantly, not move the camera after you have focus confirmation.

It doesn't need to move much, especially with a close subject like this one, to spoil it completely.

I'd forgotten about setting focus point, I have mine on centre all the time!

You could also enable 'catch in focus', but that can be hit and miss as well.

Ehhhhhhhh.....When using MF lenses the centre focus point is automatic selected. No way it will be set at an other point.

The green hexagon has some latitude to play with. Depending on which camera you use. You will notice you can turn the focus ring for a certain amount, whit out the green hexagon disappearing. The will effect critical focus.(specially with the lens set at wide open)

You might also check the dioptre setting, on your VF. That can also influence the way you "see" something in focus.

Nice to see you back Martin

In my experience too the focus confirmation is not accurate enough for close up focussing. Split prism screen is the only way to go.

Thanks peter, it is good to be back.

Yes, I'd certainly agree with this. I've got very used to positioning the ring as close as I can to the middle of the range over which the hexagon is lit, which seems to work for me.

However, unless there's a back focusing issue, the latitude you describe isn't as great (at least not on my K10D) as it would have to be, to account for the substantial focus error in the OP's picture.

So it is! I'd forgotten that.

Why is this the case, do you think? Why shouldn't it be able to use the other AF points, just because MF lens is stuck on the front?

Hi Chris,
I think it is plain old fashioned "Old School" thinking by the design dep.
Because the focus area of MF was based on the location of the split screen/RF patch in the past.

A more likely reason could be: Their is no electronic linkage between original MF lenses and modern Dslr's except the contacts who give the aperture info. ( Pentax A lenses) So how could there be communication between the movement of the focus ring and the camera electronics ??

TBH.....I don't know if selecting a different focus point is possible
using MF with DA lenses. I never tried that. I always used real MF lenses.

Just tried it out... the focus point is selectable when using a DA lens (in this case my kit lens) and manual focus but defaults to the centre point with older lenses (in this case an SMC-A 50mm f/1.7). (This was with the K20D, I assume the K10D will be identical.)

Best wishes, Kris.

Thanks Kris,
I'll guess this makes my thoughts about the lack of electronic linkage between dslr's and old mf lenses correct, as the main reason selecting different focus points is not possible.