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Thread: Sal24-70Z convince me

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    Sal24-70Z convince me

    As some of you know I converted a Zeiss Contax 28-85mm lens to sony mount. The pics are great; much better than almost anything I've seen from the 24-70 so far. Note, I'm speaking of sharpness not artistic merit.

    Unfortunately I went to Sony Style here in Kowloon yesterday and my A900 won't recognize Sony lenses. I'm sure that the reason is the converter I've been using has shorted some of the pins in the camera. I've tried to keep it covered with paper but it wears away and now no longer recognizes sony lenses.

    So I am considering buying a new body here along with the 24-70. The problem is that I keep looking at images from the lens on the a900 and the only really good performance I see is at 50mm. At both the long end and the wide end the corners are soft even at f11 let alone f8 and below that the edges soften up as well.

    I really think it is much worse than the 28-85 except at the wide end where the 28 also exhibits poor resolution in the corners at f8.

    Eventually I'll have the camera repaired but I'm at the beginning of a 3-4 month driving trip across the US so I'm considering buying a new camera and lens for that trip and dealing with the rest of the issues later.

    But unless I can feel good about buying a 24-70 it doesn't really make sense as I think I can make the current body continue to work manually just fine. I'll need to do some work to get those pinsto stop contacting the converter but back in California I can get what I need to do that.

    So show me some pics that show the 24-70 with performance nearly as good as the contax zeiss zooms and maybe I'll venture out tomorrow morning and go buy another a900 and a 24-70.

    thanks,

    Mike

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    Mike,

    I had the 28-85 in the past and I can assure you the 24-70 is even better in the corners. Any corner softness in my opinion is due to careless focusing. If you give an email address I will send you a couple of files at full res.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Re: Sal24-70Z convince me

    Quote Originally Posted by edwardkaraa View Post
    Mike,

    I had the 28-85 in the past and I can assure you the 24-70 is even better in the corners. Any corner softness in my opinion is due to careless focusing. If you give an email address I will send you a couple of files at full res.
    thanks Edward,

    My email is [email protected]. I've been pretty happy with the 28-85 even though it demands manual focus. I have a 2x sony eyepiece that works very well and conveniently.

    But if the 24-70mm is really as good maybe I'll bite the bullet. I've noted your enthusiasm but I've not yet seen any tests or shots that convince me. Those on pbase by Erik Kehffer at http://www.pbase.com/ekr/2470za_test1 are the most complete set I've seen. There are also some full size crops shown by Artaphot at http://artaphot.ch/index.php?option=...=134&Itemid=43. I've seen others that were equally unimpressive to these and few if any that were more so.

    AF definitely has its advantages along with complete exif info and the ability to use fill flash.

    thanks,

    Mike

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    Re: Sal24-70Z convince me

    Hi Mike
    The dng files at the following link were mostly taken with it (converted to DNG, but that shouldn't hurt).

    Jono's A900 samples

    Help yourself.

    Just this guy you know

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    Mike, The emails are on the way. I sent you 2 jpgs that were converted from raw with IDC, landscape style, with minor exposure corrections. All other settings are on default. Apertures used are f/5.6 for the first and f/6.7 for the second, both reasonable apertures for landscape work. I would be very interested in hearing your opinion.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    Mike, btw in the provided link from artaphot, I could only find comparisons at the 70mm setting unless I've missed something. We all know that the 24-70 is not at its best at this focal length. It works best from 24mm to 60mm, and has its better performance on the wide side from 24 to 35. IMO, at 35mm it performs better than any prime I've ever tried.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Re: Sal24-70Z convince me

    Thanks Jono. Can I assume that anything between 24 and 70 with a max aperture of 2.8 in the exif is the sal2470?

    Mike

    Quote Originally Posted by jonoslack View Post
    Hi Mike
    The dng files at the following link were mostly taken with it (converted to DNG, but that shouldn't hurt).

    Jono's A900 samples

    Help yourself.

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    Re: Sal24-70Z convince me

    thanks Edward. I'm downloading the first pic now. It's 4 a.m. though and I'm gonna get a couple hours of sleep. We leave tomorrow 4 pm and I'm hoping to sleep most of the way home.

    You are probably right about the 70mm in Artaphot's tests. He hasn't done a definitive test on the 24-70 like he has some of the others. It takes forever to download here so I didn't get the whole page loaded this time.

    Will wait a few minutes to see if the second mail arrives so I can get the download started before hitting the rack.

    Jono's samples do look better than those from Erik though.

    Mike

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    Re: Sal24-70Z convince me

    Edward your second pic never made it. May be a bandwidth problem as it is very narrow in this hotel. The first pic however did show the lens to be better than I had thought.

    Jono, thanks for the pics. You've got a great eye and lot of technical skill as well and it shows in your work.

    I've decided not to get the new combo. Not because the lens is not good enough, the pics you guys provided shows it to be better than I had suspected. No, it's not perfect but it is quite good. The reason is that I would be going into hock to get it. I have stuff I can sell but it's all at home and going on a long trip I just don't want the additional expense right now. I could probably save a couple of hundred here in HK but I'd probaby end up giving it back to Visa sometime soon in interest. Being retired and on a fixed income limits my choices somewhat.

    best,

    Mike

    Thanks for the images.

    Mike

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    Re: Sal24-70Z convince me

    Edward,

    Your second pic just arrived. What a great shot. A real testament to human ingenuity and persistance.

    I've got to say though the corners are still soft. But a little crop would not be a bad thing with such a lens if it was really an issue. I'm too picky sometimes.

    Thanks for your help.

    Best,

    Mike

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    Quote Originally Posted by docmaas View Post
    Edward,

    Your second pic just arrived. What a great shot. A real testament to human ingenuity and persistance.

    I've got to say though the corners are still soft. But a little crop would not be a bad thing with such a lens if it was really an issue. I'm too picky sometimes.

    Thanks for your help.

    Best,

    Mike
    You're most welcome! First I sent you high quality 20-25 mb files but they both bounced back, so I had to compress them to around 8 mb, hence the delay. Hope you'll get your 24-70 in the future. Have a nice trip
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Re: Sal24-70Z convince me

    Mike I am in the same boat at you, except I already have a A900 and I have the CZ 16-35mm, I want a mid zoom like the CZ 24-70mm for landscape work and want good sharp images from corner to corner and yet like you I have seen all the images on the net and although 90% of the image is sharp that last 10 percent on the corners goes soft at all F-Stops. Stephen at artaphot swears by the old minolta 28-135mm and not just at 70mm as his test only shows. I couldn't resist so I picked one up on ebay, for 350.00 and should have in a few days. I will keep all posted.

    Steven



    Quote Originally Posted by docmaas View Post

    But if the 24-70mm is really as good maybe I'll bite the bullet. I've noted your enthusiasm but I've not yet seen any tests or shots that convince me. Those on pbase by Erik Kehffer at http://www.pbase.com/ekr/2470za_test1 are the most complete set I've seen. There are also some full size crops shown by Artaphot at http://artaphot.ch/index.php?option=...=134&Itemid=43. I've seen others that were equally unimpressive to these and few if any that were more so.

    AF definitely has its advantages along with complete exif info and the ability to use fill flash.

    thanks,

    Mike

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    Re: Sal24-70Z convince me

    Quote Originally Posted by docmaas View Post
    Thanks Jono. Can I assume that anything between 24 and 70 with a max aperture of 2.8 in the exif is the sal2470?

    Mike
    Hi Mike
    Just possible that a 70 will be from the 70-300, but otherwise, yes!

    Just this guy you know

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    It just occured to me, reading a similar thread on another forum, that not many people are aware of the effects of curvature of field on extreme corners. It is not that the lens cannot make sharp corners, but the problem is that when it is focused to infinity, the corners are not in focus. I try to circumvent this problem by:

    1. composing first and then focusing: Because of the field curvature, focus/recompose produces erroneous results since the focus point location has changed.
    2. Focusing at 1/3 of the distance: Just to use the lens DOF to the maximum as the DOF is twice larger to the back than to the front.
    3. Use a peripheral AF point, not only to get 1/3 distance but to get accurate focus taking field curvature into consideration (especially for lenses with a W shaped curvature).

    I realize the most common mistakes are shooting with center AF point which will give you the sharpest center and poorest corners and focusing to infinity which also has the same effect.

    It first happened to me while shooting landscapes with the Contax 35-70 zoom, a very sharp lens with a mild field curvature. The subject is at theoretical infinity. However, I was coincidentally trying to focus on something near the image border because it had high contrast, and was very surprised that the distance scale was showing 3 meters. When I focused at the image center I got infinity as it should. This is when I realized that objects near the frame edge and others in the center, even though at the same distance to the lens, will have very different focusing distances depending on the particular field curvature characteristics of each lens.

    Therefore, I believe that "intelligent" focusing will get you rid of most if not all corner softness with the 24-70, and any other lens that suffers from field curvature.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Re: Sal24-70Z convince me

    Edward that is a brilliant explanation! thanks....
    My photoblog: http://josefskye.tumblr.com
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    Re: Sal24-70Z convince me

    Quote Originally Posted by jonoslack View Post
    Hi Mike
    Just possible that a 70 will be from the 70-300, but otherwise, yes!
    Your 70-300 can do f/2.8? I want that lens

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    Re: Sal24-70Z convince me

    Mike
    any idea about the price of 2470 in Hong Kong

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    Re: Sal24-70Z convince me

    Quote Originally Posted by edwardkaraa View Post
    It just occured to me, reading a similar thread on another forum, that not many people are aware of the effects of curvature of field on extreme corners. It is not that the lens cannot make sharp corners, but the problem is that when it is focused to infinity, the corners are not in focus. I try to circumvent this problem by:

    1. composing first and then focusing: Because of the field curvature, focus/recompose produces erroneous results since the focus point location has changed.
    2. Focusing at 1/3 of the distance: Just to use the lens DOF to the maximum as the DOF is twice larger to the back than to the front.
    3. Use a peripheral AF point, not only to get 1/3 distance but to get accurate focus taking field curvature into consideration (especially for lenses with a W shaped curvature).

    I realize the most common mistakes are shooting with center AF point which will give you the sharpest center and poorest corners and focusing to infinity which also has the same effect.

    It first happened to me while shooting landscapes with the Contax 35-70 zoom, a very sharp lens with a mild field curvature. The subject is at theoretical infinity. However, I was coincidentally trying to focus on something near the image border because it had high contrast, and was very surprised that the distance scale was showing 3 meters. When I focused at the image center I got infinity as it should. This is when I realized that objects near the frame edge and others in the center, even though at the same distance to the lens, will have very different focusing distances depending on the particular field curvature characteristics of each lens.

    Therefore, I believe that "intelligent" focusing will get you rid of most if not all corner softness with the 24-70, and any other lens that suffers from field curvature.
    Edward since I shoot a lot of lanscape stuff here in Arizona, are you saying that shooting at infinity is really not the way to go, what would you recommend to focus on? Or choose infinity then back off a little, use manual focus? I want sharp across the whole FF.

    Steven

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    It would be difficult to give any advice on this, but some trial and error should be very interesting. Even if the entire field is at infinity, I would rather focus on the closer infinity if this makes any sens There is a difference between infinity at 10 km and at 50m. Even though the AF points are not spread enough to really compensate for the field curvature, but I would rather use the lower AF point to get focus more on the foreground. I have to say that this field curvature thing is very complex, I have some photos shot at f/2.8 with perfect corners, and others at f/8 with blurry ones.
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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    Re: Sal24-70Z convince me

    thanks edward. I guess I will do some test and see. I will keep you posted.
    I just got my CZ 24-70mm and anxious to try it out.

    Steven

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    Senior Member edwardkaraa's Avatar
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    Re: Sal24-70Z convince me

    Quote Originally Posted by kuau View Post
    thanks edward. I guess I will do some test and see. I will keep you posted.
    I just got my CZ 24-70mm and anxious to try it out.

    Steven
    Congratulations Steven! I'm sure after you start using this lens, the color, 3D and microcontrast will soon make you forget the corners
    M262 ZM 25/2.8 35/1.4 50/2 85/2

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