[systemBuilder]

I just bought a 50mm F1.4 Pentax-M lens for a song (it came with an ME Super and Flash and Zoom for free.) I am wondering, however, why do the "A" series lenses seem to sell for about $110-$150 on Ebay, whereas the M-series lenses sell for $50-$100 on ebay. Is the "A" setting some incredible boon to DSLR buyers? I was thinking that if you buy a 1.4 lens, you are buying it for the F1.4 F-stop so you might as well shoot aperature priority and keep the lens on the 1.4 setting most of the time. If I wanted to shoot on "A" setting I have a Pentax-A 1.7 50mm lens for that purpose.

So are the "A" lenses much more useful with later generation pentaxes? If so, how?

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Last edited by systemBuilder; 05-16-2012 at 08:21 AM.

[Adam]

A lenses are much more convenient because you don't have to stop down to meter every time, and the camera records aperture data in the EXIF. Pentax DSLRs don't have the rod that senses how far a lens has been stopped down, so using manual lenses with them is more tedious.

BTW, you can't shoot with M lenses in Av mode; you have to be in M. Av will only work properly for lenses that have a manual diaphragm (i.e. M42 lenses).

https://www.pentaxforums.com/forums/pentax-lens-articles/110657-how-use-meter...k-x-k-7-a.html

[fuent104]

I would actually like to hear what people consider to be the advantage of using automatic exposure. I finds hal exposure to be much more precise.

[Hilo]

I can only speak for analog cameras:

Automatic exposure means you only need to focus, if you are using analog older cameras. So it all goes a lot faster. Most Pentax systems have fine lightmeters, I would guess 90% of your images will be correctly exposed in automatic modes. And, but this is a personal opinion, of the 10% that are not correctly exposed some will be more interesting images exactly because of that.

Using automatic exposure can mean a different way of photographing: one where you do not think much about your camera anymore, and instead you can focus only on who or what you are making the picture off . . . and perhaps even why

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Last edited by Hilo; 05-16-2012 at 02:21 AM.

[Jonathan Mac]

A lenses are more convenient due to the automatic exposure, however, the Pentax A lenses lack the solid metal feel of the M lenses and the aperture rings wear out because they're not tough enough to withstand so many years of use. I have only one A lens and I only use it on the A setting to avoid further damage to the aperture ring. I wouldn't pay significantly more for an A lens than for an M lens as the As have their disadvantages too.

The thing is that many people are "afraid" of manual exposure because it takes some learning or they plan to use the lens in situations where the light level varies too much to meter each time without missing shots. That's fair enough. I like the build quality of the older, fully manual lenses and for me that's more of a plus than the A setting.

[kev.pride]

"A" setting on lens does not mean automatic exposure. It simply means you can adjust the aperture via the camera & not having to use the aperture ring.

Can still use the lens as you can with any later lens totally manually - but all done in camera.

None of this can be done in camera by M/K lenses.

Thats the advantage. Simple.

[Jüri]

I've noticed that exposure is a lot more precise, when camera knows the A setting.

Also, the A setting allows to use a TTL flash. With an M lens, camera is unable to set flash power correctly and the image will be likely overexposed.

[séamuis]

I've noticed that exposure is a lot more precise, when camera knows the A setting.

Also, the A setting allows to use a TTL flash. With an M lens, camera is unable to set flash power correctly and the image will be likely overexposed.

these are your real advantages using an 'A' lens.

[RioRico]

these are your real advantages using an 'A' lens.

Indeed. I'll say that THE main advantage is ability to use pTTL flash. Any lens without 'A' contacts *can* be used with flash, but with some degree of difficulty.

I don't worry about slight exposure differences between AF|A-type lenses and others in ambient-light work, because I chimp and adjust and fix. Yes, allowing camera control via all exposure modes is useful. But pTTL flash is the main point. So I need more A lenses.

[fuent104]

I see. Thanks for the explanations! The one thing I have noticed about automatic lenses is that it is nice to be able to adjust the exposure in 1/3 stop increments, too.