A6500 with SEL24F18Z

[nzking99]

Is a6500 supporting Phase detection AF with SEL24F18Z (Zeiss Sonnar T* E 24mm F1.8 ZA)?

Lens version is 0.2 but the camera's menu (AF System) is not activated and message pop up as "Invalid with this lens" when i select the menu.

any idea what is wrong?

Thank you

[Roland Schulz]

What exactly are you adressing in the menu? Your thread is interesting to me since I receive my third (!!) SEL24F18Z copy today, had issues with two copies before.

 

I also have a a6500 and already had 2 copies of the SEL24F18Z. Both were from 12/2016 and both had some defects or issues. The first showed good sharpness in the middle, when focused to infinty. Sharpness was also very good in the the front "the same time" (like tilt/shift). The sides (not even corners) were only sharp in the front when focused to infinity. Strange, never seen this before.

 

The second copy worked quite ok wide open using AF, but stopped down focus came to the front when focused to infinity. There are two modes to focus with the a6500, don´t remember the name, but one focusses wide open, the other stopped down to the working aperture. There were differences, but never perfect.

 

With my other lenses (35 1.8, 50 1.8, 10-18 4.0 and 18-105 4.0) focus is quite fine most the time, so I don´t think it´s the camera.

 

I already had a SEL24F18Z years ago when I had a NEX7. There I never encountered any problems with AF but got rid of all the NEX system since I didn´t used it any more when I concentrated on Nikon FF.

Now I´m interested in video and came back to Sony first with the a6300 and now with the a6500.

 

 

The SEL24F18Z is a high rated lens, but actually I have to see if the third from a complete different batch will work better on my a6500.

 

What problems do you have exactly?

 

Roland.

[Guest Jaf-Photo]

That's kind of the signature lens for E Mount APSC-C. Not ideal if it has compatibility issues with A6500.

[Username]

What exactly are you adressing in the menu? Your thread is interesting to me since I receive my third (!!) SEL24F18Z copy today, had issues with two copies before.

 

I also have a a6500 and already had 2 copies of the SEL24F18Z. Both were from 12/2016 and both had some defects or issues. The first showed good sharpness in the middle, when focused to infinty. Sharpness was also very good in the the front "the same time" (like tilt/shift). The sides (not even corners) were only sharp in the front when focused to infinity. Strange, never seen this before.

 

The second copy worked quite ok wide open using AF, but stopped down focus came to the front when focused to infinity. There are two modes to focus with the a6500, don´t remember the name, but one focusses wide open, the other stopped down to the working aperture. There were differences, but never perfect.

 

With my other lenses (35 1.8, 50 1.8, 10-18 4.0 and 18-105 4.0) focus is quite fine most the time, so I don´t think it´s the camera.

 

I already had a SEL24F18Z years ago when I had a NEX7. There I never encountered any problems with AF but got rid of all the NEX system since I didn´t used it any more when I concentrated on Nikon FF.

Now I´m interested in video and came back to Sony first with the a6300 and now with the a6500.

 

 

The SEL24F18Z is a high rated lens, but actually I have to see if the third from a complete different batch will work better on my a6500.

 

What problems do you have exactly?

 

Roland.

    

Considering your experience with both examples, it sounds like a typical 

description of Curvature of Field ..... rather common with fast wide angle 

lenses. What you've observed on the sides of the frame would also have 

occurred at the top and bottom if the format had been 36x36mm square 

instead of the somewhat narrow 24x36 rectangle.   

   

Your old Nex-7 was strictly Contrast Detection AF, which is immune to 

curvature of field if you move the AF point to the desired AF target in 

your composition. OTOH, CoF wreaks havoc with phase detection AF 

which, crudely described, is an electronic rangefinder rather a means 

of judging the actual sharpness of the image at the sensor :-( 

[Roland Schulz]

Considering your experience with both examples, it sounds like a typical 

description of Curvature of Field ..... rather common with fast wide angle 

lenses. What you've observed on the sides of the frame would also have 

occurred at the top and bottom if the format had been 36x36mm square 

instead of the somewhat narrow 24x36 rectangle.   

   

Your old Nex-7 was strictly Contrast Detection AF, which is immune to 

curvature of field if you move the AF point to the desired AF target in 

your composition. OTOH, CoF wreaks havoc with phase detection AF 

which, crudely described, is an electronic rangefinder rather a means 

of judging the actual sharpness of the image at the sensor :-( 

 

But this would mean an enormous field curvature ;-), focused to infinity (trees in about 150m) and areas in the very front were sharp on the bottom!

 

Maybe the guys at Sony were to busy before christmas. I got a new sample yesterday from march 2017 and this is quite fine, razor sharp in the center and good to very good in the corners. Have to do some more tests, but it seems this copy is fine!

 

But by the way, my Nikon D3 and D4 are always prone to misfocus in special circumstances and I thought a camera that focuses in the focal plane would never have these problems - but now I know better. The a6500 as the a6300 before also often show misfocus with several lenses. Nothing is perfect.

[Roland Schulz]

Back to the initial question: I found what you mean. The option "AF system" should only be available for options when using a Sony adapter for dSLR A-mount lenses. Seems that the user can´t take any influence between PD or CD AF when using native E-mount lenses. With my combination this function is also greyed out and yes, any of my E-mount lenses (10-18, 18-105, 24 1.8, 35 1.8, 50 1.8) do show focusing errors in some circumstances even with a camera that focuses in the focal plane. I never had expected this as a problem on such a camera.

[Roland Schulz]

Ok, did some further tests. Same problem if a little less pronounced as with the samples before - very strong field curvature with the SEL24F18Z/a6500 combi that is most visible around 2.8 to 4.0. AF is also hit and miss here, especially regarding the results towards the sides.

If focus succeeds you may get good shots around 5.6, but in the end I would call this combi a piece of crap, especially for that price!

AF precision is very bad and again, never expected this from a camera that focusses in the focal plane.

[Guest Jaf-Photo]

This is perplexing. I have no issues with 24/1.8 on A6000. To the contrary, it's a joy to use. What could be the difference with A6500?