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Sony A7R - LA-EA4

Discussion in 'Sony Alpha E-Mount Cameras' started by tbyork2014, Jan 11, 2014.

  1. tbyork2014

    tbyork2014 TalkEmount Regular

    84
    Jan 11, 2014
    Hi,
    I've just joined this forum as it looks like a great place to share information. I've been searching for information on the net regarding many things associated with the A7R such as the LA-EA4, the lens-compensation app, various A7R settings, but not found what I wanted to know. I thought it would be worth sharing some of the things I've found as I'm sure someone else will have been asking the same questions - and it could save them wasting their time searching elsewhere. I finally bought this adapter as it gives me the ability to AF with the A7R until more E-mount FF lenses become available, even though there were doubts in my mind. I have to say I am happy that I bought this, as I now know more about how it performs - and it definitely performs on the A7R . In this thread, I thought I would share about my personal experience with the LA-EA4, and hopefully help those who are in the same dilemma as I was.

    Q1. The LA-EA4 has 3 cross points. How about the other 12 AF points?
    A: The majority of the other AF points focus well with horizontal lines i.e. it will have great difficulty to lock on to vertical lines and will hunt. The only exceptions are the two points on either side of the center AF point which detect vertical lines and will hunt with horizontal lines. It does help to remember what these other points are sensitive to if you do choose flexible spot AF and use points other than those 3 cross-points, so your camera doesn't hunt. The AF points are sensitive to subjects aligned like what I've illustrated below:

    11885428874_1ed7e6866e_c_d.

    Q2. It has been mentioned on certain sites that in-camera correction only works with native E-mount lenses. Does the in-camera lens correction work with A-mount lenses mounted via LA-EA4 on the A7R?
    A: For the Sony 85/1.4 Zeiss the answer is yes. The corner vignetting is corrected when this feature is set to Auto on the camera. I'm not sure about other A-mount lenses as I do not have any other Sony A-mount FF lenses to test, but perhaps Sony will be able to advise. Suffice it to say that the statement about in-camera correction only working with native E-mount lenses is not true. But do be aware that this lens (Sony 85/1.4 Zeiss) has significant longitudinal chromatic aberration (i.e. the color fringing in the out of focus areas with magenta in the areas in front of the focus point and green in those behind the focus point), which will not be corrected by in-camera correction - hence very important to get AF spot-on for wide-open shooting.

    Q3. Is the AF of LA-EA4 accurate?
    A: Yes and No. Yes if the lens is accurately aligned. No if the AF is off by a big margin. My 85/1.4 requires -14 AF microadjust for it to focus accurately at maximum aperture. From f2 onwards this is less of an issue, due to the increased DOF. In fact you can use the longitudinal chromatic aberration effect of the lens (mentioned above) to aid in microadjusting AF, to know if the AF is aligned in front or behind the focus point. FYI, my Minolta 70-210/4 beercan also needed -15 AF microadjust to be accurate with its AF. That may explain why some testers have not had as much success with the LA-EA4 and A-mount lenses.

    Q4. How fast is the AF of LA-EA4?
    A: Pretty fast even in low light, even with the screw-drive and SAM lenses I have. It focuses even faster in good light. Definitely faster than any E-mount contrast-detect AF lenses. In fact it feels as fast if not faster than (from what I recall of how) my A77 auto focused. Very impressive indeed.

    I hope this information is helpful to those of you looking at getting this accessory.

    BW,
    Boon
     
    • Like Like x 9
  2. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    Welcome, great way of introducing yourself by providing this kind of information!
     
    • Like Like x 2
  3. tbyork2014

    tbyork2014 TalkEmount Regular

    84
    Jan 11, 2014
    Thanks for the welcome, Ad. 2 further things to add.

    1) LA-EA4 has 3 settings for focus point selection selectable from A7R (through the center button): Wide i.e. all focus points (no choice for selection of certain groups of AF points unfortunately), center point, or flexible AF point selection from any of the 15-points.

    2) Turning the focusing ring in DMF does not bring up the magnified view for adjusting focus, even with screw-driven lenses. This is a feature which is useful to have for manual focus or tweaking focus, and is available with Canon lenses through the Metabones Smart adapter (even V1 which has significant vignetting at the corners can do this).

    I know it is wishful thinking, but I hope Sony does improve on the AF options available with the LA-EA4 in its firmware update (along with the option to maintain magnified view even when shutter button is being depressed, as currently pressing the shutter button while in magnified view will disable this - my current work around is to press shutter half way and then activate the magnified view for manual focusing).

    BW,
    Boon
     
    • Like Like x 2
  4. davect01

    davect01 Super Moderator

    Aug 20, 2011
    Fountain Hills, AZ
    Dave
    Agreed.

    Welcome to the forum.
     
    • Like Like x 1
  5. tbyork2014

    tbyork2014 TalkEmount Regular

    84
    Jan 11, 2014
    Thanks. Information sharing is always good. Especially when the reviewers do not answer some of the questions some of us may have.

    Boon
     
  6. tbyork2014

    tbyork2014 TalkEmount Regular

    84
    Jan 11, 2014
    BTW, I thought I would check what the light loss is due to the SLT from the LA-EA4. Hence I've tested with center metering using the LA-EA1 vs LA-EA4 to compare the light loss from the translucent mirror. With the LA-EA1 it registered as 1/200 sec, whereas the LA-EA4 registered as 1/160 sec (using same aperture and ISO), which translates as 1/3 EV light loss. I think that is the quoted light loss from the current generation of SLT, which I gather will be improved on in the next generation of SLT (supposedly by 1/3 less light loss). The quoted focus sensitivity of the current generation of SLT is -1 to 18 EV (A55/65/77/99/58), which should also apply to the LA-EA4.

    I also tested the LA-EA4 with the Sony 500/8 mirror reflex AF lens, which only uses the center AF point. It does autofocus accurately and fast even under indoor lighting. So the f8 aperture is not pushing the AF chip too far.

    Boon
     
  7. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Netherlands
    Ad Dieleman
    I had to apply "AF fine tune" (as Nikon calls it) for my lenses on the D300s as well. One thing that drove me mad and ultimately caused me to leave the DSLR world altogether, was the fact that the adjustment was only valid in a part of the zoom range. For instance, I could find a correction for 12mm on the Nikon 12-24mm but then AF beyond 14mm was off, or the other way around. Same thing for the Tokina 11-16/2.8 etc.

    Does the A7 allow for different adjustments across the zoom range when using the LA-EA4 with a zoom lens like the Minolta 70-210/4 you mentioned?
     
  8. tbyork2014

    tbyork2014 TalkEmount Regular

    84
    Jan 11, 2014
    No it doesn't. It displays as a single adjustment, which changes from lens to lens. Although I am not sure if this is the case for multiple copies of the same lens, as I do not have duplicate lenses I can try with this. But each unaligned lens I couple to the LA-EA4 starts off as 0 alignment.

    BTW, not to do with the LA-EA4 but what I learned last night about the A7R's CDAF. I noticed that in low light (and I've just confirmed it in bright light as well that) my A7R contrast-detect AF will hunt for focus if the main area of contrast is horizontal; turning the camera to portrait mode or even slightly at an angle so there is some vertical contrast results in fast AFing and lock on - that is the case wherever I placed the AF point.

    So it looks like the A7R CDAF detects the contrast in the vertical plane; that may explain why some people struggle in low light. Knowing this characteristic of the A7R (and perhaps the Nex-range), people should be able to work around by either focusing on an area with vertical contrast, or if this is not possible to rotate the camera so there is some vertical contrast for the camera to lock on (even 30-45 degrees helps a lot) and then readjust the camera back to the normal shooting position. It is a shame that they could not have cross-type contrast-detect AF as that would probably solve their AF hunting problem. With reasonable vertical contrast, the A7R locks on to focus even in a dark room quite easily (BTW, my AF illuminator is set to OFF, as this feature I've found to give poor AF lock-on with the E-mount cameras, often with the 'big dotted square').

    BW,
    Boon
     
    • Like Like x 1
  9. Davehux

    Davehux New to TalkEmount

    1
    Sep 21, 2014
    Hi just joined the forum

    I have the minolta 200mm f2.8 apo hs prime and laea4 a7r, do you know how much micro adjustment this lens needs as I fing it of when focusing wide open?
     
  10. serhan

    serhan TalkEmount All-Pro

    Aug 27, 2011
    NYC
    I have not used LA-EA4 but coming from a dslr, usually it is lens specific. Some they don't need and some needs it, not like all minolta 200mm f2.8 lenses will need it. I have Canon and survived without the adjustments, since the older cameras didn't have that option. You have to test yourself and see if it focuses accurately and adjust it if it doesn't.