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Author Topic: Sony Alpha 55/33  (Read 15274 times)
feppe
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Oh this shows up in here!


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« Reply #20 on: August 25, 2010, 11:44:36 AM »
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There are still some doubts in my mind. This convergence might be celebrated by some/many..but for primary stills shooters (ala myself) it's indeed somewhat worrying that there are compromises involved here and that Sony are indeed ok about sacrificing IQ (loss of light due to the mirror not moving) in order to achieve a viewfinder for video shooters (and phase detect AF, which is also compromised too for video)

The danger of convergence is that you have products that might appeal to a broad market but may not satisfy the specific needs of photographers or even video shooters. A jack of all and master of none. That's what I'd be concerned about.

While these are legitimate concerns from an academic perspective, it's highly questionable whether they are so from a practical one. Concerns about the mirror cutting light or introducing distortion will most likely have already been made moot by technological advances in sensors and software. I'm sure there is an impact on IQ, but whether that is something that can be seen on screen or even on print compared to traditional approaches is doubtful.

For example, when was the last time you thought "Dammit, if I could only get third of a stop more light I could get this shot! Better call it a day and go home to sulk."? Tongue

Michael, you said you had a chance to use the A560.

Did the two-second self timer (or the focus check live view) have mirror lockup at all? I figure it would be the first thing you check...  Wink

If you read the article carefully you'll see there's no MLU needed or even possible with the setup. Or did I miss the joke?

You did find the AF tracking to be good - and I correct?

That's also found in the article: "while my camera work is a bit jerky (you try following a rider moving at about 30 MPH on an irregular course, using a long lens), the focus tracking is extremely good."
« Last Edit: August 25, 2010, 11:48:44 AM by feppe » Logged

barryfitzgerald
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« Reply #21 on: August 25, 2010, 01:28:05 PM »
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The A560 is one of the 2 traditional DSLR models hence the posters question about MLU (I'm also curious to see if this is present)
As for the compromises granted to some 30% loss of light might be no big deal..it's still a point worth making.
Other issues as well are in particular the problems of shooting at a high FPS and tracking a moving subject, not the easiest thing to do with an  EVF.

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Dan Vincent
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« Reply #22 on: August 25, 2010, 01:40:13 PM »
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Quote
If you read the article carefully you'll see there's no MLU needed or even possible with the setup. Or did I miss the joke?

I was asking about the a560, which is not the same as the a33/55. Smiley I understand there's no MLU necessary for the a33/55.
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BJL
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« Reply #23 on: August 25, 2010, 01:41:49 PM »
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It appears the concept of the mirror is to overcome focusing issues with live video ... But as a landscape shooter I'm not finding much that appeals to what I do. Nice price point, but focusing is something I would prefer to do manually via live view most of the time, and giving up 1/3 to 2/3rds stop of light ... tough say, but not sure I would like that either ...
The main A55/33 virtues compared to mirrorless EVF cameras like the G1H or G2 do seem to be for high frame rates, both 7fps or 10fps stills and 30fps video, and perhaps faster focus for action photography. But then for that action photography, the 1/2 stop speed loss (reportedly 30% of light goes to the AF sensors, more than I had guessed) is going to cause a lot of complaints, whether justified or not. After all, that is about the size-based ISO speed difference between 4/3 and "APS-C" formats, and a great many people declare it to be a major disadvantage of 4/3 format! And at least when the lower speed (with lenses of equal minimum f-stop) is due to using a smaller format, it comes with the use of shorter focal lengths and smaller effective aperture diameters, and so can offer some size and weight advantage as compensation.

Maybe the next step will be Sony putting that new 16MP sensor in a new, higher spec. NEX body. But that new sensor in the latest Sony releases does seem to leave recent models like the NEX 5 and NEX VG10 camcorder looking a bit outdated already!
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billh
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« Reply #24 on: August 27, 2010, 06:54:37 AM »
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Michael, thanks for the as usual interesting and informative report!

With regards to the AF performance:

- The DPR review was not happy with the AF performance.  They felt it had trouble tracking in burst stills mode.  I wonder about two possible differences between Michael's experience and theirs.  First off, DPR could be shooting differently and seeing a different problem - e.g. maybe they are trying to track a subject moving both towards them and across the field where they could simply be failing to keep the AF sensor on the subject.  Or, perhaps the difference is between video and stills.  In video, with the aperture forced wide open there really is continuous AF tracking.  In stills it seems the camera must stop AF during exposure because when the aperture is stopped down for the exposure the AF system won't work.

Anyway, glad to see something interesting and innovative in the market.  Probably not the camera for my particular uses though.

Ken

That may be the explanation for this discrepancy. I found several videos which all seem to show impressive focus following,
Sony promotional video of moving subjects,
http://www.youtube.com/watch?v=86Yu9FJMEpg&feature=related
Video of quick AF changes as camera moves from subject to subject,
http://www.youtube.com/watch?v=b9nLcv6hLsQ&feature=related
Skate boarders,
http://www.youtube.com/watch?v=QKed3N4OZIY&feature=related
Toy speed boat with 70-300,
http://www.vimeo.com/14412907
Another short video (stock lens)?,
http://www.vimeo.com/14412969
Sony UK intro video for the Axx series:
http://www.youtube.com/watch?v=eKwLICLPUoY
Video AF-speed comparison between Canon 550D and Sony a55:
http://www.youtube.com/watch?v=kHPaVD0pHpQ

so between Michael’s report and these videos, it looks like the AF tracking works pretty well to me. I have been looking for a dual capability camera like this for my daughter to use at her children’s soccer games (keeps me from standing there in the hot sun during the summer), and for a friend in France to use to shoot a unique dog sport (Campagne) he competes in. I have sent small pocket camera that rate well in tests, but none work well, and he is not up on things photographic, so the camera has to be foolproof. He send the card from the camera to me and I process the images and video from it. I just had to find an image a breed magazine could could use on a composite cover, and none of the action shots were salvageable.
I know absolutely nothing about Sony lenses. The 70-300 f4.5-5.6 looks like a good choice for sports, assuming its AF is quick enough. Anyone know about shorter focal length lenses? I assume a zoom would be best for them to use.
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wolfnowl
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« Reply #25 on: August 28, 2010, 07:54:13 PM »
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Another review on the A55: http://www.imaging-resource.com/PRODS/AA55/AA55A.HTM

It's probably not the camera for me - don't shoot much video or high-speed work.  However, when one shows up locally I'll probably give check it out and see how it feels to hand.

Mike.
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aaykay
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« Reply #26 on: September 04, 2010, 12:02:33 AM »
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I know absolutely nothing about Sony lenses. The 70-300 f4.5-5.6 looks like a good choice for sports, assuming its AF is quick enough. Anyone know about shorter focal length lenses? I assume a zoom would be best for them to use.

I think their 16-105 (APS-C) or 16-80 (APS-C) might be wide enough (and light enough) for most purposes.  Sure there are pro-grade lenses like the Full-frame Zeiss 16-35 f/2.8 or the Zeiss 24-70 f/2.8 or their "G" lenses like the 70-200 f/2.8 or the 70-400 f/4-5.6 etc but those may be overkill for the purpose.

I think even an all-purpose lens like the Sigma 18-250 HSM (with Optical IS for the Sony Alpha mount) might get the job done pretty well.
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Dan Vincent
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« Reply #27 on: September 13, 2010, 09:50:30 AM »
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Hi Michael,

Saw your a55 update today and it seems like good news. However, one item of note.

The item about the Zeiss Cine lenses is not entirely right. The Zeiss Cine lenses are coming for standard A-Mount, not the E-Mount.

Of course, they can be used on E-Mount with the A to E adapter that Sony sells, but they are primarily being made for the traditional Minolta/Sony A-Mount.

Figured you would like to know.
« Last Edit: September 13, 2010, 10:22:55 AM by Dan Vincent » Logged

michael
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« Reply #28 on: September 13, 2010, 11:44:01 AM »
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Thanks. I've already deleted it.

I have been working on a NEX-5 update as well and simply pasted it into the wrong write-up.

Michael
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Dan Vincent
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« Reply #29 on: September 13, 2010, 01:17:46 PM »
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I don't think you need to have deleted it, as since these lenses are the standard A-mount they will be of use to all Sony/Minolta users AND E-Mount users too. a33/55/560/580 users (and assumedly any future Sony video DSLRs) can use these new Zeiss cine lenses just as much as the NEX users can with the E to A mount adapter.
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billh
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« Reply #30 on: October 01, 2010, 06:36:40 AM »
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Thanks Michel. That seems to limit the a55 as a dual purpose camera. Do you know when they will send you a GH2 to test?

Bill
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michael
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« Reply #31 on: October 01, 2010, 09:58:13 AM »
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I've asked, and I'm waiting.

Michael
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Christoph C. Feldhaim
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« Reply #32 on: October 01, 2010, 10:04:45 AM »
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I wonder what kind of camera Nikon D3S with a pellicular mirror and faster processor would be ....
Should be a killer - shouldn't it?
Just dreaming and fantasizing ...
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BartvanderWolf
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« Reply #33 on: October 01, 2010, 12:44:04 PM »
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Concerns about the mirror cutting light or introducing distortion will most likely have already been made moot by technological advances in sensors and software.

They haven't. Deflecting light out of the image forming bundle of light will reduce sensitivity. Light that doesn't contribute is lost for exposure. The only way to compensate is to amplify the remaining signal, which increases noise. Whether that noise level (= loss of dynamic range) is acceptable or not is something that different people will judge differently.

Cheers,
Bart
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ErikKaffehr
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« Reply #34 on: October 01, 2010, 05:12:46 PM »
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Hi,

There is an alternative, increase exposure 1/3 - 1/2 stop.

I don't think the light lost to the mirror causes reduction of image quality per se. What is lost is essentially sensivity.

In my view the SLT concept is very interesting. It makes an electronic viewfinder more practical. In my view it's also an advantage that we don't have moving parts, so alignment between sensor, mirror and AF may be more consistent.

A possible evolution of the concept may be a combination of phase detection type of AF fine tuned by an (optional) contrast sensing AF.

Best regards
Erik


They haven't. Deflecting light out of the image forming bundle of light will reduce sensitivity. Light that doesn't contribute is lost for exposure. The only way to compensate is to amplify the remaining signal, which increases noise. Whether that noise level (= loss of dynamic range) is acceptable or not is something that different people will judge differently.

Cheers,
Bart
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BartvanderWolf
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« Reply #35 on: October 01, 2010, 05:58:09 PM »
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Hi,

There is an alternative, increase exposure 1/3 - 1/2 stop.

I don't think the light lost to the mirror causes reduction of image quality per se. What is lost is essentially sensivity.

Hi Erik,

Indeed, but they somehow need to get to an ISO sensitivity that is somewhat comparable with the standards, and other cameras. Therefore they still need to compensate the overall sensitivity. According to some comparisons on other websites, the performance of a Nikon 700 at ISO 1600, produces similar noise as the Sony alpha 55 at ISO 400. I have not conducted the comparison myself, but Iliah Borg is a knowledgeable guy who would be able to spot shortcomings in the testing methodology.

Cheers,
Bart
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ErikKaffehr
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« Reply #36 on: October 02, 2010, 02:23:34 AM »
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Hi,

I won't argue with Iliah Borg. But I'd suggest the comparing a full frame sensor with an APS-C sensor is like comparing apples and oranges. Also, the Nikon sensor is like sensivity champ.

I'm more like tripod user, so increasing exposure is normally fine for me. What I argue that the concept will not loose dynamic range compared to DSLR if the image is correctly exposed to the right.

The way I see it, some light is lost for AF-sensor making it possible to electronic view finder with phase detection AF. I would prefer to be able to remove the translucent mirror from the optical path when using Live View for focusing but it seems it will not be possible on the forthcoming more advanced model.

An EVF can show histogram before the shoot, pinpoint auto focus with all lenses using live view and also a virtual horizon. All this things would be important to me. Especially, I have a 400/4.5 lens which I use sometimes with a 2X extender. Focusing that is trial and error, mostly error. So I really need live view.

Finally, I presume that the idea that Sony came up with translucent has much to do with cost. I guess that the moving mirrors in DSLRs and also the high quality penta prisms needed for a great viewfinder are quite expensive in manufacture.

Best regards
Erik





Hi Erik,

Indeed, but they somehow need to get to an ISO sensitivity that is somewhat comparable with the standards, and other cameras. Therefore they still need to compensate the overall sensitivity. According to some comparisons on other websites, the performance of a Nikon 700 at ISO 1600, produces similar noise as the Sony alpha 55 at ISO 400. I have not conducted the comparison myself, but Iliah Borg is a knowledgeable guy who would be able to spot shortcomings in the testing methodology.

Cheers,
Bart
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Patrik
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« Reply #37 on: October 02, 2010, 03:59:12 PM »
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I am a studio portrait photographer and I am really interested in the A55´s facedetection, does the evf work in the studio with the camera on manual. The exposure is of course to dark for the ambient light in the studio but perfect for my Elinchrome flashes, so does the evf add gain to make it useable like on the Panasonic G2 I know it doesn´t work on the Sony 550 liveview ? I hope Michael can try this out !?
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Eli Burakian
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« Reply #38 on: October 15, 2010, 08:52:53 PM »
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Forgive me if this has already been mentioned, but I don't think it has.  Anyways, does this technology mean that rapid fire shooting can be done silently?  For wedding, event, wildlife, and even sporting photography, this would be a huge advantage over my current SLR for these "quiet" situations.

Thanks

Eli
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Dan Vincent
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« Reply #39 on: October 21, 2010, 12:12:30 PM »
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Forgive me if this has already been mentioned, but I don't think it has.  Anyways, does this technology mean that rapid fire shooting can be done silently?  For wedding, event, wildlife, and even sporting photography, this would be a huge advantage over my current SLR for these "quiet" situations.

Thanks

Eli

It is not silent, but it is certainly significantly quieter since there is no flapping mirror. The camera still has a mechanical focal plane shutter.
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