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Thread: Sony A850 2 questions Focus Screen/Af adjust

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    Administrator, Instructor Guy Mancuso's Avatar
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    Sony A850 2 questions Focus Screen/Af adjust

    Part A: Well folks as i get more familiar with this cam . I have a couple questions. I noticed a Type M focus screen which says manual focus to me and it appears to work well with 2.8 and faster lens which all three of mine are. Obvious question anyone using it and what is your gut impressions of it. One thing mentioned it clearly shows focus in or out better.

    Part B: Just got the Minolta 200mm and i maybe back focusing ever so slightly. I do need to test and get on tripod but - for front focus and + for back focus. Anyone adjusted there lenses or find the need to adjust them.

    BTW anyone following it looks like I did buy a counterfeit battery and ordered a new one from B&H today.

    Wondering now if the Type M focusing screen is worth it
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    I have a type M screen in my A900. I find manual focusing much easier than with the stock screen, especially in lower light. It shows depth of field somewhat better as well (the stock screen shows much more in focus than actually is in focus, the M screen does so as well, but not as much).

    I did adjust the front and read focus for most of my lenses. It's a bit frustrating as the front/rear focus can change on some lenses as the lens is stopped down (the 35/1.4 and 50/1.4 are particularly noticeable). It also changes to some degree with focus distance so any settings are a bit of a compromise. I haven't tried to adjust my zoom lenses as I think there are just too many variables. It is most important for lenses that you use wide open at relatively close focus as being off even slightly will be noticeable.

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    Senior Member douglasf13's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Nearly all of my lenses needed at least a little AF micro-adjustment. Of course, it can be dependent on focus distance and aperture used, so YMMV.

    Another thing to keep in mind is that the center focus point is larger than it looks, so make sure that you're not accidentally focusing on something in front or behind what you intend to. The A900's double cross center point with the additional f2.8 AF sensor is the biggest in the business, AFAIK:

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    Senior Member Eoin's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Guy, I use the M screen in one of my a900s. The primary reason was for the manual focus rokkor 58mm f:/1.2.

    It seems to (m screen) register in and out of focus somewhat clearer than the stock screen but in all honesty there is not a lot in it. It helps but it's not a huge difference.

    Using either body with AF lenses I wouldn't even notice the difference between the M or G screens.
    A7II, FE 35, 55 C/Y 18, 28, 85, 100, 28-85

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    If you want a nice bright viewfinder and rely on autofocus, stick with the stock screen. If you want to be able to judge focus rather than trusting the camera get the M screen. The stock screen is a pretty standard autofocus camera screen.

    I have the M screen and it is pretty good. I have a hard time judging focus on it, or at least I have a hard time consistently nailing critical focus with manual focus lenses. I don't know if this has to do with the screen itself or if mine isn't perfectly aligned and needs to be shimmed. The Sony M screen is $50 - $75 and a real aftermarket screen is a whole lot more. For that price, I can't think of any reason not to get it. The M screen kind of makes the A900 feel like an old film camera (in a good way). I have had some weirdness with my meter in the A900 and I don't know whether the M screen has any effect on that.

    I look forward to hearing your thoughts on the 200. I will probably be selling my Leica 180/2.8 and that is a definite contender. I only have one Minolta AF lens, but focus in any decent light is spot on.

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Bill the 200 is really nice so far . Need to get out and test it but very small and light and focuses like a rocket. Pretty sweet. It will get used doing the fashion stuff in January reason I wanted to get it pretty quick. I will get some shots going this weekend and post

    I may just get the screen. I am pretty visual with focus and trust nothing but my eye even with AF.

    There not expensive so maybe worth the try at least.

    Doug I here you on the AF sizing it is bigger than the lighted diode that is what set me off on the AF micro adjust and I was just playing around and noticed it. I'm going to mount on a tripod and test at least the 135 and 200 just to be sure.

    Can't thank you folks enough I am usually the answer man so it is really nice I get the help when I need it. LOL

    Love this place if i say so myself.
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Quote Originally Posted by Bill_Green View Post
    I have had some weirdness with my meter in the A900 and I don't know whether the M screen has any effect on that.
    Did you change to the M screen type in the menu?

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    I ran through all of my lenses checking MFA and came up with some interesting results. My 80's 28-135 checked out perfect at all tested FL and focus distances. Same with the 135 & 70-400. The APO lens was sort of all over the map.

    I tested at each ft. mark on the distance scale and each marked FL on zooms, entering the MFA value in a table for each. For the zoom that was not consistent I picked a compromise value based on most used FL and distance, and I keep the corrections for other settings handy in case I need them for some situation. Took me about a week of checking 1 or two lenses each evening after work, but IMHO it was worth the trouble.

    The M screen does improve the ability to MF and check DOF, but I only use it for macro these days since I find the brighter view with the G screen to be of more use to me in general. If you were local I'd let you borrow the M screen so you could decide if it's worth buying.
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    Senior Member pegelli's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    All my f 2.8 or wider lenses (including a 200/2.8 HS the OP is asking about) needed a bit of adjustment, but I don't need anyting beyond +/- 6. All my smaller aperture zooms are fine and I didn't bother to adjust as the AF deviation tends to be well in the dof range.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    The M screen is permanently in the camera. It is clearly darker but very effective not only for manual focusing lenses, but also it is much easier to see if the AF has slightly missed. If I was using only AF lenses I might use the stock screen for the extra brightness, but I shoot MF lenses and override the AF quite often so the M screen is a no brainer for me.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Senior Member Braeside's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Guy,

    Nice to hear you have joined the Sony FF ranks.

    There is also a Sony FDA-FL1AM Grid L Type Focus Screen for the A900 which I find useful for getting things straight. Doesn't improve MF however.

    BTW I have had to put an AF micro adjust on every lens I have, my A900 seems to have a consistent offset of about 5 (needing -5 correction), I guess I should have got the body re-calibrated, but didn't want to risk anything going wrong so I live with it, at least I can easily correct with the AF micro adjustments.
    David Anderson

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Thanks David yes going to test lenses this weekend . I was seeing some back focus with the 200mm and will check the 135 as well
    Photography is all about experimentation and without it you will never learn art.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Quote Originally Posted by Braeside View Post
    Guy,

    Nice to hear you have joined the Sony FF ranks.

    There is also a Sony FDA-FL1AM Grid L Type Focus Screen for the A900 which I find useful for getting things straight. Doesn't improve MF however.

    BTW I have had to put an AF micro adjust on every lens I have, my A900 seems to have a consistent offset of about 5 (needing -5 correction), I guess I should have got the body re-calibrated, but didn't want to risk anything going wrong so I live with it, at least I can easily correct with the AF micro adjustments.
    I use the grid screen as well because I'm congenitally incompetent at getting horizons level - unless I'm using a tripod!

    I found my 70-400 very sharp with no microadjustment needed and I use it at full aperture most of the time. My ZA 24-70 needed a a few points of micro, and my Sigma 70 mm macro needed none. When I had a 135 ZA it was spot on. (Hope it is for you, too, Guy!)

    Bill

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    Administrator, Instructor Guy Mancuso's Avatar
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Little strange 135 Zeiss +3 and the Minolta 200 -4

    Now to go shoot for real and see
    Photography is all about experimentation and without it you will never learn art.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Geez...I do not even know how to do it. My 85/1.4 G obviously need an adjustment.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    I'm playing sponge in here also. Gonna need to make some adjustments to few of my lenses. Or at least check them.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    I have the L-type (grid) and the M-type screens. I used the M-type quite a bit but went back to using the L-type, since I liked the brighter view it afforded, in addition to the available grid.

    Having said that, I do feel that the M-type, since it is a coarser type, does provide the ability to estimate the in-focus/out-of-focus better, especially for manual-focus lenses. I would have been truly happy if there was an LM (grid, bright and coarse) type screen available.
    A900 with a few lenses, flashes etc.

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    Re: Sony A850 2 questions Focus Screen/Af adjust

    Anybody try this tool yet? I'm planning on getting one and doing my lens for my A-900.

  19. #19
    davemj98
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    Re: Sony A850 2 questions Focus Screen/Af adjust

    I have the grid on both of my 900's; shooting cross country races puts me on uneven ground often.
    Dave

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