[bdery]

Do we (or can we) somehow create a database or list of lenses that seemingly perform very well in terms of AF accuracy and response? How could we go about that? Do we just look at the review section one lens at a time, take note of what the review section thinks it's performing for AF rating and do it that way?

You can certainly use the data I provide when doing reviews to compare lenses. Simply because I always use the exact same setup and lighting conditions (and measure the incident light before each measurement step, as an added safety). So graphs I provide can be directly compared to others.

Of course, I test in ONE set of conditions. It would be impossible to test all possible scenarios of course, so I use a controlled setup to be able to compare lenses. Absolute speed values will vary, but should remain comparable between lenses.

[bdery]

Do we (or can we) somehow create a database or list of lenses that seemingly perform very well in terms of AF accuracy and response? How could we go about that? Do we just look at the review section one lens at a time, take note of what the review section thinks it's performing for AF rating and do it that way?

You can certainly use the data I provide when doing reviews to compare lenses. Simply because I always use the exact same setup and lighting conditions (and measure the incident light before each measurement step, as an added safety). So graphs I provide can be directly compared to others.

Of course, I test in ONE set of conditions. It would be impossible to test all possible scenarios of course, so I use a controlled setup to be able to compare lenses. Absolute speed values will vary, but should remain comparable between lenses.

[bassek]

There was a test in a German magazine (Colorfoto maybe, last year perhaps?) where they tested AF on many camera brands and lenses.
Oddly enough, Pentax was among the top performers. There were differences between lenses.

When I encounter AF problems it's either a) really dark b) due to my many mistakes. I can't honestly blame the camera or the lens.

Seb

[BruceBanner]

You can certainly use the data I provide when doing reviews to compare lenses. Simply because I always use the exact same setup and lighting conditions (and measure the incident light before each measurement step, as an added safety). So graphs I provide can be directly compared to others.

Of course, I test in ONE set of conditions. It would be impossible to test all possible scenarios of course, so I use a controlled setup to be able to compare lenses. Absolute speed values will vary, but should remain comparable between lenses.

Do you have a link to your reviews?

[awscreo]

So, what is the proper technique for using screw drive af lenses? Or af lenses in general.

I tried this before - I had a model posing for me, I was shooting tamron 70-200 with a single focus point, AFS. Aimed at her eye, pressed af, snapped a pic - not perfect focus. Focus to infinity, try again. Not perfect. I had to do that few times to achieve a good sharpness level on her eye. Sometimes however it just snaps to focus and all is well. Afternoon daylight.

DFA 28-105 just focuses almost every time. Not sure what causes it to miss sometimes, but when aimed at the same point second time, it focuses perfectly.

So, what would be the human error in this situation? I genuinely would like to know to improve my workflow.

[Adam]

This is what I found out for myself this year. I decided to stop using AF entirely and master MF for all my lenses, even on jobs/events! I decided in order to increase my skill set for MF I had to be very strict with myself and resist the urge to toggle that AF button on. Indeed I believe the experience worked, and to this day I use MF more than AF, like a great deal more!
However I did swap over my Samyang 85/1.4 for the FA 77/1.8 to gain back AF and a lighter more compact lens. I did get caught out on a couple of events where I felt AF would have really helped, just like you say.

But the Facebook post made me think about my future purchases, for example, instead of saving for a FA43/1.9 should I continue saving and just aim for the DFA 50/1.4, not because I am necessarily needing that focal length and aperture (nor would I relish the additional size and weight) but rather the lens perhaps just has a far higher AF success rate in AF.C mode etc.

I would really like to see a proper Pentax review of AF between more classical lenses (the FA Limited's for example) vs some of the newer glass (DFA's).



So is there a general consensus that certain lens AF tech is better than other for focusing? I mean I understand some are quieter, some give quick shift etc, but what if all you care about is precision and speed, what lens tech is supposed to deliver best?

We recently did a homepage post that compared the different technologies. Again, it's hard to generalize, because a lot of factors are lens-specific. But its hard to go wrong with DC, PLM, and ring type SDM in my opinion. They all do their job well.

[BruceBanner]

You can certainly use the data I provide when doing reviews to compare lenses. Simply because I always use the exact same setup and lighting conditions (and measure the incident light before each measurement step, as an added safety). So graphs I provide can be directly compared to others.

Of course, I test in ONE set of conditions. It would be impossible to test all possible scenarios of course, so I use a controlled setup to be able to compare lenses. Absolute speed values will vary, but should remain comparable between lenses.

So, what is the proper technique for using screw drive af lenses? Or af lenses in general.

I tried this before - I had a model posing for me, I was shooting tamron 70-200 with a single focus point, AFS. Aimed at her eye, pressed af, snapped a pic - not perfect focus. Focus to infinity, try again. Not perfect. I had to do that few times to achieve a good sharpness level on her eye. Sometimes however it just snaps to focus and all is well. Afternoon daylight.

DFA 28-105 just focuses almost every time. Not sure what causes it to miss sometimes, but when aimed at the same point second time, it focuses perfectly.

So, what would be the human error in this situation? I genuinely would like to know to improve my workflow.

I would suggest you head over here and read this recent post and discovery I made; A Pentax Hidden Feature Perhaps? - Page 2 - PentaxForums.com

[awscreo]

I would suggest you head over here and read this recent post and discovery I made; A Pentax Hidden Feature Perhaps? - Page 2 - PentaxForums.com

I'll try, but Tamron is known for having issues focusing in live view. Also, I'm trying to figure out of my technique is lacking in ovf, so far I can't pin down what I'm doing wrong. Something is off, because both da 50 1.8 and Tammy 70-200 can't reliably focus where I point them to.

[bdery]

Do you have a link to your reviews?

That's pretty much all of the recent reviews except the DFA 50, but here goes anyway:

Articles by bdery | PentaxForums.com

I don't think there's much missing regarding lenses.

You can double-check using that link:

Articles - bernard-dery

[BruceBanner]

I'll try, but Tamron is known for having issues focusing in live view. Also, I'm trying to figure out of my technique is lacking in ovf, so far I can't pin down what I'm doing wrong. Something is off, because both da 50 1.8 and Tammy 70-200 can't reliably focus where I point them to.

Have you done any Fine Adjustments (in the camera menu) for the lenses you are having trouble with? What Auto Focus Settings are you using in your camera etc. There's a lot to address here.

That's pretty much all of the recent reviews except the DFA 50, but here goes anyway:

Articles by bdery | PentaxForums.com

I don't think there's much missing regarding lenses.

You can double-check using that link:

Articles - bernard-dery

Thanks Bernard!

[awscreo]

Have you done any Fine Adjustments (in the camera menu) for the lenses you are having trouble with? What Auto Focus Settings are you using in your camera etc. There's a lot to address here.




Thanks Bernard!

I have indeed. But, I noticed that values are different for different distance. For example, at close distances I can use - 7 af adjustment value with good results. But same values don't work well for objects at far distances (best value for that is +3 for me).

I also tried calibrating da 50 1.8, similar results. At different distances values that work differ.

I use afs, single af point, usually in the middle (I think that's the most precise point in K-1?). I try to aim it at things that have some contrast in them, like an eye in portraits, where skin should theoretically be contrasted with a shadow inside the eye, or the pupil. I'm. Not sure what side objects work best with this af system. Maybe eye is too small with full body portraits. I have higher success rate aiming at the horizon at infinity, I guess the strong separation of sky vs horizon line makes it easier to obtain good focus.

My Tamron 90 2.8 macro is much more reliable at focusing, I haven't noticed back/front focusing, it seems to always work fine.

[BruceBanner]

I have indeed. But, I noticed that values are different for different distance. For example, at close distances I can use - 7 af adjustment value with good results. But same values don't work well for objects at far distances (best value for that is +3 for me).

I also tried calibrating da 50 1.8, similar results. At different distances values that work differ.

I use afs, single af point, usually in the middle (I think that's the most precise point in K-1?). I try to aim it at things that have some contrast in them, like an eye in portraits, where skin should theoretically be contrasted with a shadow inside the eye, or the pupil. I'm. Not sure what side objects work best with this af system. Maybe eye is too small with full body portraits. I have higher success rate aiming at the horizon at infinity, I guess the strong separation of sky vs horizon line makes it easier to obtain good focus.

My Tamron 90 2.8 macro is much more reliable at focusing, I haven't noticed back/front focusing, it seems to always work fine.

I too found FA a bit hit or miss.

Honestly it's probably just your high expectations in conjunction with a subpar OVF experience. I really don't use my OVF that much these days, and I have an expensive Tenpa 1.22 magnifier in place to assist with determining focus.

Here's what I have concluded;

1) OVF with AF is hit or miss at times, when I use OVF I do it for AF.C and burst shooting purposes.

2) If I have the time for a shot (such as studio/static objects or location shoots) I use the Live View, I get way more feedback if something is in focus with that. Using Face Detection Zoom I find the very best. Monopodding can also help with that.

3) When I do use the OVF (with my Tenpa 1.22) and I'm not AF.C bursting, I quite often just use Manual Focus, I can frame things quicker and just shoot.

4) My top trick is to use Manual Focus yet also use back button focusing, and before taking the shot set the Shooting Mode to Continuous High Burst, then when you get confirmation through the OVF that focus has been obtained, start shooting, but as you're shooting slowly rotate the focus ring throughout the burst of 1-10 images or so. Somewhere in that bunch one will be a sharper image than the rest, use that frame, delete the rest. Practice this technique and you can do it with subjects not even on the AF point, just judge with your eyes. Point is, maximise the single best advantage digital cameras gave us over film, disposable shots

People don't seem to understand that OVF PDAF is a range, not a single point, this accounts for all the back focusing and what not, the system struggles at many times to find that exactly perfect sharpness point. If you have lenses with Quickshift, use it, as you take the shot burst and ever so slightly change the focus throughout the shot, this increases your chances of landing a shot that has better sharpness than the rest.

Honestly, I've lowered my expectations of AF, I now think of it as something to get me to the ball park of where I want focus, but I now have to deploy tricks to get the sharpest shot possible (which I detailed above).

New lenses (like the DFA 50/1.4 etc) may make all that work unnecessary, but comes with a hefty price tag.

[awscreo]

I too found FA a bit hit or miss.

Honestly it's probably just your high expectations in conjunction with a subpar OVF experience. I really don't use my OVF that much these days, and I have an expensive Tenpa 1.22 magnifier in place to assist with determining focus.

Here's what I have concluded;

1) OVF with AF is hit or miss at times, when I use OVF I do it for AF.C and burst shooting purposes.

2) If I have the time for a shot (such as studio/static objects or location shoots) I use the Live View, I get way more feedback if something is in focus with that. Using Face Detection Zoom I find the very best. Monopodding can also help with that.

3) When I do use the OVF (with my Tenpa 1.22) and I'm not AF.C bursting, I quite often just use Manual Focus, I can frame things quicker and just shoot.

4) My top trick is to use Manual Focus yet also use back button focusing, and before taking the shot set the Shooting Mode to Continuous High Burst, then when you get confirmation through the OVF that focus has been obtained, start shooting, but as you're shooting slowly rotate the focus ring throughout the burst of 1-10 images or so. Somewhere in that bunch one will be a sharper image than the rest, use that frame, delete the rest. Practice this technique and you can do it with subjects not even on the AF point, just judge with your eyes. Point is, maximise the single best advantage digital cameras gave us over film, disposable shots

People don't seem to understand that OVF PDAF is a range, not a single point, this accounts for all the back focusing and what not, the system struggles at many times to find that exactly perfect sharpness point. If you have lenses with Quickshift, use it, as you take the shot burst and ever so slightly change the focus throughout the shot, this increases your chances of landing a shot that has better sharpness than the rest.

Honestly, I've lowered my expectations of AF, I now think of it as something to get me to the ball park of where I want focus, but I now have to deploy tricks to get the sharpest shot possible (which I detailed above).

New lenses (like the DFA 50/1.4 etc) may make all that work unnecessary, but comes with a hefty price tag.

Thank you for sharing your techniques, I'll give them a go. Ultimately, i'm hoping to replace all of my screw drive lenses with newer ones asap. Just waiting for the DFA 70-200 f4, and saving up for the DFA 50 1.4
Hopefully I'll be over my af troubles after that)

[BruceBanner]

Thank you for sharing your techniques, I'll give them a go. Ultimately, i'm hoping to replace all of my screw drive lenses with newer ones asap. Just waiting for the DFA 70-200 f4, and saving up for the DFA 50 1.4
Hopefully I'll be over my af troubles after that)

If it's any consolation I used to use nothing but AF. I used SEL Single Point mode and constantly moved the AF point around the grid to choose my AF point. As I was researching lenses a few of the MF (Manual Focus) ones grabbed my attention. I decided before buying one that I should try and determine if I could manage MF as up until that point I really hadn't properly tried. I did a stint of a few months and found the whole process quite liberating. Sure I missed some shots, but overall I was a more happier shooter. If I messed up then I felt the problem lied with me rather than blaming a less than stella AF system. Eventually I bought that lens (Samyang 85/1.4) and you can see the results for yourself below;

Search: sammy85 | Flickr

The entire experience taught me that we rely to heavily on AF, and that actually it can take longer to get the shot with it switched on vs just using MF! Of course there are situations that are unavoidable and require AF but I discovered that's still the minority of time for this shooter. My friend laughs at me when I decided to sell the Samyang 85 and eventually save for a FA77 (just so that I could have AF in case I needed it on a similar focal length lens), yet however he sees me constantly using it in MF mode

[awscreo]

If it's any consolation I used to use nothing but AF. I used SEL Single Point mode and constantly moved the AF point around the grid to choose my AF point. As I was researching lenses a few of the MF (Manual Focus) ones grabbed my attention. I decided before buying one that I should try and determine if I could manage MF as up until that point I really hadn't properly tried. I did a stint of a few months and found the whole process quite liberating. Sure I missed some shots, but overall I was a more happier shooter. If I messed up then I felt the problem lied with me rather than blaming a less than stella AF system. Eventually I bought that lens (Samyang 85/1.4) and you can see the results for yourself below;

Search: sammy85 | Flickr

The entire experience taught me that we rely to heavily on AF, and that actually it can take longer to get the shot with it switched on vs just using MF! Of course there are situations that are unavoidable and require AF but I discovered that's still the minority of time for this shooter. My friend laughs at me when I decided to sell the Samyang 85 and eventually save for a FA77 (just so that I could have AF in case I needed it on a similar focal length lens), yet however he sees me constantly using it in MF mode

I owned the SY 85 1.4 for the m43 mount before, it's a great lens. But focusing with the EVF was quite challenging sometimes, not sure how much harder it is with a normal OVF.

What did grab my interest though - the Pentax-A 70-210 F4. I looked around, and seems the IQ is very very good at f8-11 (which I typically use when I'm out doing landscape work). I might pick one up and give it a go, it's like $60, and if IQ is comparable to the Tammy 70-200 i'd rather carry 680g than more than 1kg with me