Author Topic: A900 - Lens IQ Sample Images and Discussion  (Read 31833 times)

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Offline Rob aka [minolta mad]

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #15 on: January 19, 2009, 08:00:18 PM »
Quote
"I am not sure about the performance of the Sony 50mm f1.4 on the A900!"

Looks like the donuts you get with the 500 mirror.


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Offline Stef.

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #16 on: January 19, 2009, 08:08:01 PM »
Rob- I fully agree! I think it performs awful on the A900 while it does a really good job on the A700!
Bill- see above. It's a shame that it does well on the A700 but badly on the A900.
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Offline Bill

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #17 on: January 19, 2009, 08:19:03 PM »
People always talk about bokeh.  We have a current thread about it here on this forum.

I am no expert, but...

I am fairly convinced that bokeh has a lot to do with the quality and type of light being cast.  A sharp, metallic or water based reflection from bright sunlight seems to be the worst.

My reasons for this thought are these...

I can take the same lens, use the same settings, and produce beautiful bokeh and horrendous bokeh within a matter of minutes.  Directly reflected sunlight seems to be a major factor in bad bokeh.  Limiting this seems to greatly improve bokeh.  As I stated in another thread, perhaps this is why the STF works so well.  It has a pair of apertures, one smaller than the other.  I wonder if this setup limits light in such a way that bokeh turns to cream.

Just my thoughts.

Stef,

Try the same exact shot without the bright reflections off the foliage and see how it turns out.

Bill
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Offline Stef.

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #18 on: January 19, 2009, 08:21:17 PM »
I will Bill. I really don't want to accept that I might not be able to use my prime anymore... I see your point regarding the CZs- and yes they fab. but I would love to be able to use the mugh lighter 50mm as well!
Stef.

O.K. I have done another test with the Sony 50mm f1.4 - this time in more controlled lighting situation:
Camera Sony A900 was mounted onto the Manfrotto tripod with SSM set to off. Two Sony flashes were used as lighting sources.
ISO 200
WB daylight- corrected in ACR
no sharpening in ACR but slight sharpening in PS CS4
Exif included

@f1.4


@f1.7


@f5.6


@f8


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« Last Edit: January 29, 2009, 10:59:48 PM by Stef. »
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Offline Simon [aka springtide]

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #19 on: January 19, 2009, 08:53:25 PM »
I will Bill. I really don't want to accept that I might not be able to use my prime anymore... I see your point regarding the CZs- and yes they fab. but I would love to be able to use the mugh lighter 50mm as well!
Stef.

That is one of the disadvantages of the new Sigma 50mm f1.4 (I have one on order) - size!

Note that the new Sigma is supposed to be much better on FF than the Sony, see:

http://www.dpreview.com/lensreviews/sony_50_1p4_m15/
http://www.dpreview.com/lensreviews/sigma_50_1p4_c16/

The Sigma is much bigger.  It's 77mm filter thread while the Sony is 55mm.  And is 505g while the Sony is 222g.
So it's more like the size and weight of the CZ85, which has a filter of 72mm and is 640g.


Bill, that was a very interesting post re: bokeh of the CZ24-70 you posted, showing the CZ24-70 producing very similar 'donuts' as the Sony 50mm above (if a little less pronounced) in harsh lighting - but when the light was much better and and generally softer - it really did improve.
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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #20 on: January 19, 2009, 10:06:48 PM »
O.K. these are shot in a bit more controlled lighting and I am much happier considering they are all shot @ f1.4:



100% crop:




100% crop:


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Offline Simon [aka springtide]

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #21 on: January 19, 2009, 10:11:58 PM »

Stef, any chance on looking at the corner sharpness? 

I think the centre of the Sony 50mm is supposed to be great, but has poor falloff at the edges (hence why dpreview thought the lens was excellent on APS-C, but not so great on FF)
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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #22 on: January 19, 2009, 10:16:19 PM »
Here is a last one and yes will post corner sharpness:



100% crop:


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P.S I am much happier now ;)
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Offline Stef.

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #23 on: January 19, 2009, 10:27:47 PM »
The last two: again Sony 50mm f1.4 @ f1.4:



100% crop:


The corner sharpness only makes sense to me if seen on an image @f8 or higher as with f1.4 the out of focus areas are blurred anyway.

Will try and shot something at f8
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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #24 on: January 19, 2009, 10:49:45 PM »
Here the duck shot @ f8 incl. two crops from the corners:







Not sure though how useful these crops are as the ground was out of focus even @ f8. At least the corners are not smeared.
Stef.

P.S. Enough of the 50mm lens at least for now ;)
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Offline Stef.

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #25 on: January 19, 2009, 10:59:48 PM »
Absolutely last one: again Sony 50mm f1.4 @ f8



Corner 100% crops:




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Offline Simon [aka springtide]

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #26 on: January 19, 2009, 11:31:06 PM »
Hi Stef,
I guess I'm trying to work out whether I made the right decision for the Sigma over the Sony :)  Jessops were selling the Sony 50mm f1.4 for £185 around Xmas, but I've been holding off for the Sigma which I've managed to find for £300 (so a far bit extra)

I found with my 50mm f1.7 that the resolution falloff for portraits was terrible if you ended up shooting off centre with the A900 (i.e.  when centering the face using 'rule of thirds'). This wasn't so noticeable with the A700 was this resolution falloff coupled with flare as well as non-circular aperture blades of the f1.7 has forced me to upgrade my 50mm.  

I looked at the review of the Sony 50mm on DPreview and was a little disappointed with the review on FF.  Take a look at the resolution (MTF) figures for FF:
http://www.dpreview.com/lensreviews/sony_50_1p4_m15/page5.asp
It's a pretty cool resolution chart at DP, as it lets you see the image circle and the resolution for each aperture to compare.  

Note that the new Sigma is supposed to be the 'bees knees' either, as they are supposed to suffer the usual Sigma inconsistent BB/FF calibration issues, although I did read some posts on the black forum about similar issues with the Sony.
My decision was for the more expensive Sigma, but I will send it for calibration if there is any sign of FF/BF issues (rather than return).  

Anyway, this A900 is the financial bane of my life!  But I love it!
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Offline Bill

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #27 on: January 19, 2009, 11:44:42 PM »
Simon,

You should be able to correct any focus issues with the microfocus adjustment on the a900, so no worries there.

The sigma 50mm is the way to go if you want to shoot from wide open to f/2.4.  If you plan on shooting most of your shots at smaller apertures than f/5.6, then the Sony may have been the better choice.

If I buy a really fast lens, it is to shoot mostly wide open, or close to it!  Therefore, if you are the same, you are probably in great shape!

Just my opinion.

Bill
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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #28 on: January 20, 2009, 12:30:52 AM »
I agree with Bill. I don't think you made w rong decision at all Simon apart from buying the CZ 24-70mm should you not have it yet... the only advantage I see with the 50mm over the CZ is weight. Can't see me using it a lot as I don't usually use my camera in crappy light anyhow. Hardly ever shot film with over ISO200 nor digital.
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Offline Simon [aka springtide]

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Re: A900 - Lens IQ Sample Images and Discussion
« Reply #29 on: January 20, 2009, 09:51:21 AM »
@Bill:  The problem with the FF/GF issues with the Sigma lenses, is that (sometimes) depending on the focus distance, the same lens will either FF or BF.  e.g.  up close it might FF, but at longer distances BF - so can't always be corrected 'in-camera'.  It's also very interesting with the lens performance between the two lenses.  You would have thought if a lens performs much better at f1.4 than another lens, it would also perform better at smaller apertures (within reason) - but that's obviously not the case with these two lenses.  But you are right, I'm probably very rarely going to be using the 50mm above f5.6.

I agree with Bill. I don't think you made w rong decision at all Simon apart from buying the CZ 24-70mm should you not have it yet... the only advantage I see with the 50mm over the CZ is weight. Can't see me using it a lot as I don't usually use my camera in crappy light anyhow. Hardly ever shot film with over ISO200 nor digital.
Stef.
P.S. Yep- it is getting expensive...

If I'm honest and I know this will not go down well with the CZ2470 owners, but I'm currently holding off buying the CZ due to the poor bokeh under specific lighting conditions, which although not a deal breaker - before splashing out £1200 on the CZ I want to wait to see what my options are.  I know the specific lighting conditions are usually harsh lighting conditions which you usually shouldn't be shooting anyway, but I have seen a similar effect under other conditions (there were some examples to links that I posted in the other thread).

The new Sigma 24-70 f2.8 HSM is due soon (sometime in Feb for Nikon/Canon and a few months later for Sony) which RRP is £800 (currently £650 pre-order).  As it's double the price of the previous version, I'm hoping that it might be an alternative to the CZ.  It's not ideal as it's 82mm filter, which means probably spending a few hundred £ more for filters compared to the CZ (as I already have a set of 77mm's), but for me I only want to do these lens purchases 'once' from now on.
The second alternative might be (if it exists) the Sony 24-105G f4 SSM (there have been several rumours).  For me, I'm thinking this might be a nice option for slightly better focal range.

I must admit that I kind of like my Tamron 28-75 at the moment.  The bokeh seems pretty good (although I must admit we are not getting harsh lighting conditions at the moment).  It's pretty sharp by f4 and I actually like the fact it's a little soft at f2.8.  There is so much resolution with the A900, that I'm liking the option of 'toning it down' a bit.  I use this focal length mainly for snapping photos of the children, so the reality is that I don't actually need super high resolution with this focal range (landscapes are usually 16-35) - and if I do, I'd switch to the 50mm or 85mm primes as they give me more options for larger apertures.  I have been thinking about a 35mm f1.4 to add to the range of primes, but only thinking!

Just an observation with CZ (and I know this has been said before by other members), CZ do appear to go after absolute resolution rather than trying to get the best bokeh possible.  I know someone stated this when I got the CZ85 compared to the KM85G - but I must be honest it didn't mean that much to me at the time.

Anyway, so thats where I am.  Waiting for the reviews of the new Sigma, and then waiting for it's availability in Sony mount, and maybe if the Sony 24-105G is released - maybe waiting for that one.  And if the other two don't meet expectations, I'll get the CZ.
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