[marius]

Hello
I'm planing to purchase some old but good manual focus lenses for my k20.
I never used manual focus lenses and need some help from members please.

My question are:
1. Is it difficult to work with MF? I mean do I have focus confirmation from my camera? For example on AF I hear a little sound from my K20 when the lens focuses. Is there the same way when using MF? If yes then it is easy right?

2. All the MF lenses have focus confirmation from my camera. A reply on thsi question will help me choosing the lenses. I don't want to make a mistake.

I'm a beginner in photography especially in MF. If someone can reply to my questions above I'll greatly appreciate this.

Thanks.

[Mike Cash]

Yes, focus confirmation will work.

If you plan to do much use of MF lenses you may wish to consider changing your focus screen to one with a split-prism. Look in the accessory section for any of a zillion discussions on "focus screen", "split-prism", or "Katz Eye" for lots of detail.

[OregonJim]

As Mike said, focus confirmation will work - but it might slow you down. After you practice focusing for awhile, you'll find that you can do it faster than the camera - it helps to ignore the focus confirmation at that point and just trust your eyes. A split prism screen helps too, especially when your eyes get tired.

[Lowell Goudge]

if you really want to do manual focus, you should consider at some point getting a split image viewfinder.

you may find some MF lenses difficult to focus, if you go to extremes. Specifically very fast lenses because they get a little soft wide open, and some slow lenses due to high depth of field.

[marius]

Thank you All!!

If you do not mind I'll put here some lenses I would like to purchase. Maybe you can help me with some ideas about hem. If they are good or not.

Thanks again

[Marc Sabatella]

Right, the confirmation is often slower than doing it yourself, as often by the time it beeps and you react, you're already past the point where you want to be, so you end up going back and forth and back and forth. Which is what you'd generally do manually anyhow. Uless you turn the ring *incredibly* slowly, stopping after each fraction of a millimeter, to make sure you stop when you should - which is even slower. I'll occasionally use the focus confirmation (with beep turn *off*) to double check my results - focus manually, then see if the heaxgon comes on.

Like anything else that is manual, MF takes practice, but can be certainly be learned. It's way easier to do with a lens *designed* to be focused manually, becaue the focus ring has lots of travel and gives some resistance allowing you to be precise in your movements. It's also easier with wide aperture lenses than the kit lens, because they will show less DOF, baking it easier to tell when the subject is in focus. Although if you are actually *shooting* at apertures larger than f/2.8, there are other issues that comes into play - due to the design of the focus screen, the viewfinder shows too much in focus comapred to what you actually get. That can also be dealt with through practice, but those are the situations where I'm mostly likely to use the focs confirmation to help me out.

Don't forget the K20D has 'catch in focus' which can be quite usefull

[thomascdk]

Just installed the KatzEye. What an improvement! I find that the focus confirmation is very forgiving. It confirms focus in quite an interval compared to the focus screen's actual focus (that didn't sound right - not an English speaker).

[marius]

Don't forget the K20D has 'catch in focus' which can be quite usefull

Do I need to use manual A lenses only? or does 'catch in focus' works with any MF lens?

Do I need to use manual A lenses only? or does 'catch in focus' works with any MF lens?

Any old MF lens will do. If you are using a manual aperture lens it's more complex, actually manual aperture lenses don't really work satisfactorily.

[GeneV]

Right, the confirmation is often slower than doing it yourself, as often by the time it beeps and you react, you're already past the point where you want to be, so you end up going back and forth and back and forth. Which is what you'd generally do manually anyhow. Uless you turn the ring *incredibly* slowly, stopping after each fraction of a millimeter, to make sure you stop when you should - which is even slower.

I've found that to be the case as well. Relying on the confirmation leads to an overshot almost every time.

It's too bad I scratched my Chinese split screen putting it in. At least it wasn't a Katzeye.

[Lowell Goudge]

one thing to remember when picking manual focus lenses, and / or using AF lenses for manual focus is that there is a trade off between focusing speed and focusing accuracy.

You need to look at the focusing collar and how many degrees it takes to move from minimum focus to infinity.

some lenses including my Sigma 70-200 F2.8 have only 90 degrees. In MF this makes it very quick to get close but impossible to get accurate. My vivitar 400mm F5.6 has 330 degrees of rotation. very precise but impossible to focus quickly.

My Vivitar Series 1 70-210 F3.5 (version 1) has 180 degrees, a good compromise

[OregonJim]

Good tips, Lowell. Short throw focus rings are useful for fast moving targets, but you need to stop down considerably to increase DOF to mask any minor focus error.

The Viv S1 70-210 feels about right to me, too. I've grown fond of the single ring push-pull MF zooms - now I'm filling out my Tamron Adaptall2 collection.

[Canada_Rockies]

Don't forget the K20D has 'catch in focus' which can be quite usefull

All Pentax AF SLR cameras will do CIF with a manual focus lens and the camera in AF.S.

Do I need to use manual A lenses only? or does 'catch in focus' works with any MF lens?

If it is a lens, it will work.

I've found that to be the case as well. Relying on the confirmation leads to an overshot almost every time.

It's too bad I scratched my Chinese split screen putting it in. At least it wasn't a Katzeye.

As one who has used MF lenses continuously from 1961, I can say that the technique that works is to rock back and forth between too far and too close. After some decent practice time, you should be able to do it in no more than four movements, even if you lens is wide open. Stopped down, you can do it in less. Overshoot, Overcorrect in the opposite direction, nail it. This works best with lenses with long throw focus rings, as your over/under is not very far from the actual focus point.

[marius]

One more question please. Maybe is a silly question.

Until now I used only AF lenses and done some good prints. By changing to MF lenses will this negatively affects my prints? I mean, will the photo resolution change? I think will be the same resolution right? ...maybe better?
Thanks.