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AF only lens

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steephill

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Many people bemoan the short throw of focus rings on AF lenses especially in comparison to the silky mechanics of a manual focus prime. I would guess that removing the manual focus option could significantly reduce the cost of a lens. The model here is the existence of the DA-L series with their mechanical design compromises.

How many here would buy an AF only lens if it were significantly cheaper than an optically identical MF/AF version?

--
Steve

http://www.pbase.com/steephill
 
I would not want an AF only lens.
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I'm thankful to still be able to...
 
Hi Steve,

I shoot AF probably 99+% of the time, and find some short focus throw lenses not that bad a compromise, but I would find an AF only lens too compromised and would not buy one.

I can conceive of an AF only lens that I would use though. It would have to offer the option of using a pretty sophisticated semi automatic focus limiter with a very short range.

Scott
 
That would depend on how good the IQ is for the price, and the focal length. I would give up MF to have a 24mm f2.0 prime for under $200.

Doubt it will ever happen though, it is nice to have the ability to touch up the focus in troublesome situations.

Interesting thought.

Lloyd
--

“For every problem there is a solution which is simple, clean and wrong.” Henry Louis Mencken

http://lloydshell.blogspot.com/
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WSSA #354

 
Interesting question. I definitely would not give up MF for macro lens. However, for wide angle and long tele lenses, if the AF is accurate and reliable and the lens is good quality and significantly cheaper, why not?
 
sure i would, MF has its place, but for some work all you really need is AF... throw in a good focus limiter too.
--
Mike from Canada

"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."

'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'



http://www.airliners.net/search/photo.search?sort_order=views%20DESC&first_this_page=0&page_limit=180&&emailsearch=mighty_mike88%40hotmail.com&thumbnails=
 
m43 lenses - which I use (a GF1 and all the Lumix primes) - are not AF only but their MF "by wire" is lame enough to make it close to unusable. Some of these lenses are real gems though, such as the 20mm 1.7 which for all intent you might call and AF only lens.

However the reason I decided to invest in the Pentax system is to have some real "classical" photography sensations with soon-to-be retro technologies such as mirrors and MF enabled lenses ;)

I understand this might not be everybody's concern but I feel that these as well are part of what people like in Pentax...

--
Gregory Dziedzic
 
steephill said:
How many here would buy an AF only lens if it were significantly cheaper than an optically identical MF/AF version?
Click to expand...
Two reasons, wait - make that three:
  • most likely, this will be done in cheap, low-quality kit lenses - which I won't buy anyway
  • I doubt there will be that much of a price difference
and most important:
  • while I mostly use AF, it's not perfect and of course it can fail. Unless they'll have an AF system similar to how our eyes works I'd like to be able to take the control when I need it. And by that I'm not necessarily talking about manual focus; often just prefocusing near the subject then using AF helps.
Alex S.
 
Olympus already tried AF only lenses and it was one of the causes of OM system failure. I'd hate to see Pentax following this path.
--

Through a Pentax Limited prime things may appear sharper than they actually are...
http://www.pentaxphotogallery.com/jaroslavhoudek
 
There is quite a lot of focusing pronblems which can not be solved with AF.

For example when you want to have both the foreground and background within the DOF you may need to focus at a distance where there is nothing to focus on.

With a prime which has an DOF scale it is easy: you focus on the foreground, remember the distance, focus on the background and set the focus nad f number at a distance where both the forground and background are within the DOF for some f number. The distance indications of APS-C lenses are not so precise as e.g on primes for film MF cameras, but still it helps to get adeqaute DOF without using unnecessarily big f numbers and losing resolution to difraction.

Zooms usually do not have a DOF scale, but with some experience you can still guess at the needed aperture, find the near and far focusing point and focus at one third of the maximal distance.

Even if you are not able to focus using the image in the viewfinder, you can focus manually and use the focus confirmation indicator of the AF mechanism.

I agree that when you make only snapshots AF may be all you need. For carefully composed images, especially when you are a tripod type of a photagraper MF is sometimes necessary.
 
. . . They could make a lens essentially totally weather sealed (not just resistant) by eliminating the manual focusing mechanism and designing them as internal focusing and internal zoom -- a solid housing. . . ?

They could offer a precise electronic readout of focus plane distance and a supply a manual (by wire) override finely adjustable by something like an e-dial on the body. They could also have selectable multi-speed motor control for rough and fine focus adjustment.

The casing could be designed to be impact resistant as well, and the factory could offer a reasonably economical housing replacement/weather proofing and lens calibration certification service so used lens "condition" could essentially become a notion from the past.

What if this ended up being the highest-quality line of lenses instead of the el cheapos?

Scott
 
Almost every P&S camera has an AF only lens and those who own them love it, this suggests there is a large marked for AF only lenses, the question is could that market spill into the SLR realm?
--
Mike from Canada

"I am not a great photographer! God is a great creator! All I do is capture His creation with the tools He has provided me."

'I like to think so far outside the box that it would require a telephoto lens just to see the box!' ~ 'My Quote :)'



http://www.airliners.net/search/photo.search?sort_order=views%20DESC&first_this_page=0&page_limit=180&&emailsearch=mighty_mike88%40hotmail.com&thumbnails=
 
With the lens lock on the right hand side of the Pentax bodies, it is very easy to use your index finger to depress it, thus pulling back the AF screw, to allow the cheaters Quick shift on any lens. The MF ratio might not be good for fine tuning focus, but when a lens starts to hunt, it is really nice to be able to get the focus close manually.

Another nice feature of this is that it allows focus trapping on AF lenses without a MF/AF switch. Sure the AF motor will spin, but as it can't change the focus, it is only when the subject moves into focus or the lens is manually focus, that the shutter trips.

Thank you
Russell
 
Thank you Russell. Now it is easier to use my 31, 43 & 77 in MF.

Earl
 
You could have focus controls on the camera body. Hell, they could be variable gain, or you set the gain, or whatever... it could be better than what we have today.

In other words, focus by wire only.

That said, I doubt it would be better in practice, at least for the first few generations.
--
Why yes, I AM colorblind.
 
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