1. Reminder: Please use our affiliate links for holiday shopping!

Focus Accuracy and Comparison of ZD 150mm ƒ2 and 50-200 SWD

Discussion in 'Adapted Lenses' started by Phocal, May 10, 2015.

  1. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    Last week I ran thru the Focus Tune procedure on my ZD 150mm ƒ2.0 and then went out shooting. I came back with not one useable photo and I was pretty upset and not happy with the lens / EC-20 combination. Over the last two days I took my time and went back thru the procedure. I ended up not making any changes to the EC-20 but did change what I had the lens set at and the EC-14. I was not feeling very confident with not changing any of the settings when using the EC-20, but figured I would go with it for now. I decided that I would also bring along the ZD 50-200 SWD to test out it's accuracy. I have not yet ran the procedure on the SWD because I just got the software and the 150 was my main concern, but I will when I get time. After 1000's of photos with the SWD I believe the accuracy to be about dead on with just the lens and with the EC-14. Today was my first time using the SWD with the EC-20.

    To test the results after making the adjustments I wanted to shoot an animal and be able to run thru all combinations on said animal. After careful thought I decided to hit the zoo and find the flamingos. I knew I could get close enough to them and that there was nothing in the way of taking the photographs. Was also hoping they would be sleeping and that I could photograph just one the entire time. Well I got somewhat lucky, I was able to run thru all combos with the 150 but had to use a different bird for the SWD.

    The test was conducted using the center focus point placed on the eye of the flamingo. Camera was set to Aperture Priority, ISO 200, S-AF/Man, H mode, and placed on my tripod and gimbal. I would shoot a short 1 second burst then defocus lens and repeat. I did this several times for each combination. Doing the Focus Tune procedure I learned that the lens will not focus to the exact same spot each time, there is some error. That was why I did multiple burst with each combination. I wanted to see how the SWD compared to the 150 so I set it 158mm (could not get it to exactly 150 and after a few attempts I gave up). I did also shoot some photos at the full 200mm to test it out. All combinations were shot wide-open.

    Because I wanted to conduct a real world test, all photos have been given my fast edit job. This is just a quick edit that I will do to see the viability of a photograph to continue with additional editing. I did not do any of my normal spot editing, all editing effected the entire photograph.

    ZD 150mm
    p1168530127-6.

    ZD 50-200 SWD @158mm
    p1168533323-6.

    ZD 150mm + EC-14
    p1168530097-6.

    ZD 50-200 SWD + EC-14 @158mm
    p1168531549-6.

    ZD 150mm + EC-20
    p1168530109-6.

    ZD 50-200 SWD + EC-20 @158mm
    p1168533194-6.

    The biggest surprise was how well the SWD performed with the EC-20. To me it looks like the focus is about spot on with the EC-20 also. The focus speed was a bit slower then using the EC-14 or lens alone, but was not that bad. The results are enough that I am going to sell my Canon FD 400mm and just use the SWD with EC-20 when I need 800mm of reach. Because I like that combo so much, here are a few more with the lens at max zoom.

    ZD 50-200 SWD + EC-20 @200mm
    p1168531817-6.

    ZD 50-200 SWD + EC-20 @200mm
    p1168531873-6.

    ZD 50-200 SWD + EC-20 @200mm
    [​IMG]

    Here is a shot that I am really happy with using the ZD 150mm wide-open and the reason that I purchased this lens.


    Something I realized is I need to get some ND filters if I want to shoot this thing wide-open on a bright day. For the above photo I switched to ISO 100 to drop the shutter speed because when the sun came out from behind a cloud 1/8000 was not fast enough.

    I will have to say that I am happy with the performance of both lenses with either of the TC's. I think the 150 w/ EC-20 may still be a little off, will go shoot some wildlife with it soon to see how well it works out.

    Any and all comments are welcome along with any feedback. Keep in mind the photographs were not taken with composition in mind. They all were taken with center focus point on the eye of a flamingo (except maybe the full zoom SWD shots, I can't remember on those). I have also enabled download of full resolution photos if anyone wants to get a better look at them.

    Regards,

    Ronnie
     
    • Winner Winner x 2
    • Informative Informative x 1
  2. Rudy

    Rudy Mu-43 Veteran

    449
    Jan 24, 2013
    Oakland, CA
    My understanding is that focus tuning is needed on cameras that use phase detect sensors that are physically separated from the image sensor.
    These would be seeing the image via a secondary mirror when the main mirror in a DSLR is down. The focus tuning compensates for the inevitable difference in distance of the phase detect sensors vs. image sensor due to tolerances in the mirror assembly.
    The EM-1, which is what you seem to be using for this test has the phase detect pixels on the image sensor itself, so there would be no variations.
    So, I don't understand what focus tuning would buy you in this setup...
    Rudy
     
  3. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    That was initially my understanding, but Olympus has but the ability to do micro adjust so there must be a reasoning behind it. After seeing the results that @faithblinded@faithblinded got using the Focus Tune software I went ahead and ordered it. From doing the procedure there is error in the focusing of the 4/3 lenses that can be corrected in camera. After doing the adjustments I am getting much sharper images then before. I know I read someplace why it was needed with on sensor PDAF, but I can't find it now.

    Ronnie
     
  4. tkbslc

    tkbslc Mu-43 Hall of Famer

    phase detect works by using the differences in phases of light to calculate how far the lens needs to move it's elements to adjust focus. You can have issues where the AF sensor off the mirror is out of perfect alignment with the sensor on an SLR. That is not an issue with mirrorless. But the other issue you can have is a lens that is not starting at "zero" for lack of a better description. The AF sensor says move to position 25 to achieve focus. Lens thinks it is on zero and moves 25 positions. However the lens was miscalibrated and it was actually starting from position -4, meaning it is only at position 21 when all is said and done and you have poor focus. Phase detect is not like Contrast detect where it sits and samples focus continually until it is perfected. It just calculates where focus will be and goes there (which is why it is so great for tracking and speed). If the lens doesn't go where it was told, focus will be off.

    If it was just a matter of the body being off due to the mirror path, then every lens would need the same correction and it would be a simple matter. Sadly, that is not the case.
     
    • Informative Informative x 1
  5. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    Thank you......that was more or less what I had heard/read someplace else and after seeing the results first hand I am a believer. Just surprised how perfect my SWD seems with no adjustments made.
     
  6. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    At a glance I can't think of any reason why the distance would be different however in practice I've found I needed +5 on the tele end and -3 on the wide on one of my lenses, using the EC-14 it needed -5 on both (35-100m f2.0 at 100mm f2.0 this is a difference of around 5mm at distance 3 meters). The interesting part for me was without the focus adjust on the EC-14 at the wide end it would actually focus slightly past infinity (at closer focusing distances it was very hard to tell any difference at all).

    One reason I can think of is that the polarizer (or PD part of the sensor stack) may be a different thickness than the bayer filter of the rest of the sensor and there is a slight difference depending on the focal length between where it thinks is in focus vs reality. Shooting wide open at closer distances body movement is going to make most of this moot, however it's best to start with the most accurate so that by the time the picture is taken the deviations are less likely to add up to out of focus.
     
  7. eteless

    eteless Mu-43 All-Pro

    Jun 20, 2014
    To expand on that slightly, when it's hunting the camera tells the lens to go to the end of range -> the lens starts moving (towards infinity or closest, whichever the camera specified) -> The body tells it to stop and the lens stops focusing and announces its current position and waits for instructions -> the camera tells the lens to move to X position (based on what it's last position was). The lens itself can only really say "moving", "stopped at X due to interrupt" and "at the position you requested", the body has all the smarts (it can say other things related to aperture/IS/etc, and there's a handshake when it's first attached which defines all of the ranges it can operate at naturally).
     
    • Like Like x 1
  8. Rudy

    Rudy Mu-43 Veteran

    449
    Jan 24, 2013
    Oakland, CA
    If it really runs open loop then this seems like a poor implementation on the EM-1.
    Since the camera does contrast detect for native u4/3 there is no reason why it could not self calibrate the phase detect.
    Move the 4/3 lens using the phase detect sensor to where it thinks it should go and then do fine adjusts until the contrast detect says it's perfect.
    Store the difference as an adjustment in the lens and be done. Sounds like a firmware update worth asking for...
    Rudy
     
  9. Ross the fiddler

    Ross the fiddler Mu-43 Hall of Famer

    My recently acquired 50-200 SWD lens benefits from some adjustment (at the long end) on the E-M1 as I think the lens may vary.
     
  10. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    Following along as best I can. This interests me because I have a 50-200 SWD that seems fine native, but degrades slightly with the ec-14, and poor with the ec-20. So I'd like to try and adjust focus. How necessary is the software? Targets are cheap.

    Thanks
     
  11. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    The software in my honest opinion is required. Your lens will not focus at the exact same spot every time, there is some error. If you just shoot a target at a setting (setting being the micro adjust setting) and look at it, it may be spot on but the next time it could front focus just a little. With the software, you take several shots at each setting and it analyzes the photos and shows a chart with the zero line (average of focus spot for each setting). After you get it down to the setting needed you can do a focus consistency check for that setting by shooting a bunch of photos and the software will group them into sets of 5 or 10. After I got each setting I did this with 30 shots and used the 5 shot grouping. Being the type who likes to tinker, I also did this for the settings on either side of the one determined to be optimal. This helped to confirm to me that I had the correct setting.

    I am not saying you can't do it without the software, it just makes it a whole lot easier. I shot a bird and different setting and looked on my camera while out in the field, then again when I got home. This was before the targets for the system arrived. I got it to +13 as being optimal (this was with the EC-20) and ended up with +15 after using the software. So, you can get close.....I may have eventually ended up at +15, but how much time and how many ruined photos (could have missed a great photo because I did not have it dialed in yet) later would that have been? Oh, the target is pretty slick with how you set it up so everything is perpendicular and right......not sure you could get that on your own with homemade targets.

    You spend all this money on camera and lenses........$100 to make sure everything is running at it's peak performance is chump change. For me it's worth it and with plans to get more 4/3 lenses (which honestly are the best bang for your dollar of any system out there) it would be stupid not to drop the cash for this.

    I have not run my 50-200 thru it yet and until the rains stop next week will not have a chance. But looking at my photos I feel it is about perfect, so I got lucky with the SWD but had to do a lot with the 150mm. If I had felt that my SWD was off, I would have gotten the software awhile ago.
     
    • Agree Agree x 1
  12. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    Would have to be a pretty sophisticated set up. The lens never focuses to the exact same spot, there is error every time it focuses. Not sure the camera would have the processing power to take a bunch of shots and determine a zero line and best possible setting.

    Besides, it is not that hard to do with the right equipment (which is cheap).
     
  13. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    I finally got around to focus tuning the 50-200 with the EC-20 TC. Focus with it was too soft. I don't think I'd ever had an in focus shot with it.

    The process is easy, but tedious. I estimated the final adjustment. One day I'll go back to do the fine, one-step tune.

    Results were very good. Getting a shot in perfect focus with a hand held 800mm equivalent is still tough for me, but at least I can get them now. Surprisingly, focusing is much faster than it was. It still hunts once in awhile, but with a little ore-focus, it was quite snappy most of the time. I didn't expect such a difference, but there was.

    Still best resting on something solid, but I suspect I will be just as good and likely better with it than a MF lens. So I scratched a list of wanna have adapted long telephotos off my list.

    Picking a fast-moving bird or insect out of the air is still a dream, but the situation is much improved. This lens is so versatile. As much as I want the 40-150 Pro, it's hard to justify.

    Anyway, here is my sharpest shot with the EC-20. It's not a great picture of anything, just a dead flower head, but shows the best I could get with the camera supported. What do you think? Is it pretty sharp or am I a victim of wishful thinking?
    https://flic.kr/p/wNarcq
     
  14. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    Looks pretty good but hard to really tell for sure, lot going on in that photo. Take a photo of a pet or wild animal/bird, that will help you see fine detail and how well it is working. Was that shot from autofocus or did you manual get focus?
     
  15. Speedliner

    Speedliner Mu-43 All-Pro

    Mar 2, 2015
    Southern NJ, USA
    Rob
    Autofocus on the dead flower head.
     
  16. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    Looks pretty good.........I have yet to use my 50-200 with the EC-20 in the wild. Then again I have not really been out in the last month and when I have gone I have taken the 150/2. But I am confident in using it for when I need 400mm of reach and will use it over my Canon FD 400mm ƒ4.5 that I have to stop down to close to ƒ7 anyways.
     
    • Like Like x 1