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Author Topic: My take on the Sony Alpha 7/7r  (Read 17375 times)

Christoph C. Feldhaim

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Re: My take on the Sony Alpha 7/7r
« Reply #20 on: November 08, 2013, 05:27:36 pm »

I'm afraid people using the high resolution A7R will be disappointed when using their beloved old Leica and Contax wideangles with an adapter. Tolerances are extremely tight here. I'm curious on people actually testing this and reporting.

ErikKaffehr

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Re: My take on the Sony Alpha 7/7r
« Reply #21 on: November 09, 2013, 03:49:00 am »

Hi,

Tolerances my be less of a problem than suggested by many. Adding an extra mount introduces extra opportunity for error, but those errors are always alignment errors. In real world subjects are not aligned very well with the sensor. Where you focus you get excellent sharpness even with a system out of alignment.

So I would suggest that lens alignment problems are in part a test chart only problem. Or if you are shooting a brick wall, how do you know the camera is aligned with the wall?

The real issue may rather be that all lenses are not created equal. Some of the Leica lenses are excellent, but I am pretty sure that many are not so perfect and some may be tricky. With Biogon type lenses there is an additional issue that the optical package on the sensors introduces astigmatism, this was one of the reasons Leica used such a weak IR filter on the M8. On the M9 they went for a thicker filter.

The Hartblei HCam is often used with a Mirex TS adapter and I understand that combo produces excellent images.

Best regards
Erik




I'm afraid people using the high resolution A7R will be disappointed when using their beloved old Leica and Contax wideangles with an adapter. Tolerances are extremely tight here. I'm curious on people actually testing this and reporting.
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Erik Kaffehr
 

TMARK

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Re: My take on the Sony Alpha 7/7r
« Reply #22 on: November 09, 2013, 11:41:37 am »

The alignment problem is overblown.  I have several Photodiox adapters, F to EOS, V to EOS, V to F, Mam. 645 F,  None show any noticeable alignment issues.  I say noticeable because I haven't (and won't) shoot a test chart unless I was copying art.

Hi,

Tolerances my be less of a problem than suggested by many. Adding an extra mount introduces extra opportunity for error, but those errors are always alignment errors. In real world subjects are not aligned very well with the sensor. Where you focus you get excellent sharpness even with a system out of alignment.

So I would suggest that lens alignment problems are in part a test chart only problem. Or if you are shooting a brick wall, how do you know the camera is aligned with the wall?

The real issue may rather be that all lenses are not created equal. Some of the Leica lenses are excellent, but I am pretty sure that many are not so perfect and some may be tricky. With Biogon type lenses there is an additional issue that the optical package on the sensors introduces astigmatism, this was one of the reasons Leica used such a weak IR filter on the M8. On the M9 they went for a thicker filter.

The Hartblei HCam is often used with a Mirex TS adapter and I understand that combo produces excellent images.

Best regards
Erik




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Isaac

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Re: My take on the Sony Alpha 7/7r
« Reply #23 on: November 10, 2013, 01:30:26 pm »

Sony have an adaptor for A mount (but when you add the cost to the body it's not that attractive for A mount users) ... As an A mount user I'm a lot more interested in a native mount body than this.

Quote
Asked what message Sony has for A-mount users with large lenses that do not suit the shorter back focus of E-mount cameras, Sony UK's Alpha product manager Takahiro Hirata, said: ‘We will not quit A-mount product lines. We will have both product lines.'

Quote
At the press screening told Yoshiyuki Nogama to a video-oriented SLR with A-mount is going on. It will compete with the Canon EOS 5D Mark III will have Ultra HD (4K). We guess that it is a further development of the Sony A99. Sony boss also told that Sony later comes with a really fast camera for action photography.

« Last Edit: November 10, 2013, 01:44:06 pm by Isaac »
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adanac

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Re: My take on the Sony Alpha 7/7r
« Reply #24 on: November 10, 2013, 01:55:01 pm »

I'm afraid people using the high resolution A7R will be disappointed when using their beloved old Leica and Contax wideangles with an adapter. Tolerances are extremely tight here. I'm curious on people actually testing this and reporting.

I shot the A7r this week with a 10$ C/Y - E mount adapter and my faithful Contax Zeiss Distagon 28/2.8. No problems... lovely in fact.

SLR lenses are not going to be problematic in the way that many rangefinder lenses will. Bonus: While I felt some of my Contax optics felt huge and clunky on the NEX-5N, the combo of very slightly larger body, built in viewfinder, good grip, and overall design, I find that compact SLR lenses do not feel out of place at all on the A7 cameras.
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Telecaster

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Re: My take on the Sony Alpha 7/7r
« Reply #25 on: November 10, 2013, 02:01:12 pm »

My feeling is that the Alpha 7r in particular may present a similar problem to the D800, namely most folks' lenses and technique are not up to the megapixel count. They are really turning it into a 20 to 25mp camera.

Time for me to again beat one of my favorite drums: Adobe et al. should add a true-RGB mode to their RAW converters. Each RGBG array converted into a single output pixel with non-interpolated RGB values.

-Dave-
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hjulenissen

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Re: My take on the Sony Alpha 7/7r
« Reply #26 on: November 10, 2013, 03:08:43 pm »

Time for me to again beat one of my favorite drums: Adobe et al. should add a true-RGB mode to their RAW converters. Each RGBG array converted into a single output pixel with non-interpolated RGB values.

-Dave-
If you are to convert the 4 r-g-g-b sub pixels into one r-g-b fullcolor pixel, you still want to do interpolation in order to correct the offset (otherwise, the three r-g-b outputs won't be cosited).

-h
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geesbert

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Re: My take on the Sony Alpha 7/7r
« Reply #27 on: November 10, 2013, 04:22:23 pm »

The best thing about this Camera is, that as a Canon, Sony alpha, Pentax or Leica user I can now get access to a 36MP sensor without having to buy new lenses, like I would with a Nikon d800. I can use nearly any lens I own (apart for MFT). I can even mount it more easily onto a view camera with schneider glass than any canon due to the shorter flange distance. The price is fantastic.

I really hope tethered live view is possible, though I read somewhere on sony's site it is not. I could still hook up an HDMI screen for that or a tablet by NFC.
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Telecaster

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Re: My take on the Sony Alpha 7/7r
« Reply #28 on: November 11, 2013, 05:09:05 pm »

If you are to convert the 4 r-g-g-b sub pixels into one r-g-b fullcolor pixel, you still want to do interpolation in order to correct the offset (otherwise, the three r-g-b outputs won't be cosited).

Yeah, you're likely right about that. At least the sub-samples for each output pixel are all directly adjacent to each other...should reduce artifacts as well as provide tonal benefits.

-Dave-
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eronald

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Re: My take on the Sony Alpha 7/7r
« Reply #29 on: November 11, 2013, 08:18:29 pm »

Time for me to again beat one of my favorite drums: Adobe et al. should add a true-RGB mode to their RAW converters. Each RGBG array converted into a single output pixel with non-interpolated RGB values.

-Dave-

dcraw
rpp

Edmund
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Telecaster

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Re: My take on the Sony Alpha 7/7r
« Reply #30 on: November 12, 2013, 12:28:24 am »

dcraw
rpp
Edmund

Yeah, I have that. Works fine, and has been useful from the beginning of the digital era. But I mean one or more of the big commercial apps. Getting Adobe, for example, to really pay attention to tonality in RAW conversion over the past decade has been like pulling teeth.

-Dave-
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hjulenissen

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Re: My take on the Sony Alpha 7/7r
« Reply #31 on: November 12, 2013, 03:58:28 am »

Yeah, you're likely right about that. At least the sub-samples for each output pixel are all directly adjacent to each other...should reduce artifacts as well as provide tonal benefits.

-Dave-
I think that the optimum image quality can be (most easily) had by:
1. Doing demosaic, deconvolution/sharpening, color correction etc on the raw image as good as you can. I.e. correct camera flaws as well as possible and generate a generic image representation that is a superset of the camera capabilities.
2. Doing the best downscale that you can to whatever output grid is desired, pre-compensate (if needed) for known output medium deficiencies.

I don't think that doing fancy stuff within the Bayer domain is going to easily beat the procedure above for pure image quality. But it might spend significantly less cpu/memory resources. There are papers describing direct mappings from Bayer data into lowres LCD representations, suitable for low-power cameras with LCD preview.

-h
« Last Edit: November 12, 2013, 04:03:56 am by hjulenissen »
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Isaac

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Re: My take on the Sony Alpha 7/7r
« Reply #32 on: November 13, 2013, 01:06:51 pm »

I think for most folks, FF is too expensive to be worthwhile right now.

Q: Do you think that full-frame sensors will ever be meaningfully cheaper?
A: Sony is the number one manufacturer of imaging sensors, and if we can sell a lot of them, the price will come down!

;-)
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Jim Kasson

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Re: My take on the Sony Alpha 7/7r
« Reply #33 on: November 13, 2013, 04:54:07 pm »

Q: Do you think that full-frame sensors will ever be meaningfully cheaper?
A: Sony is the number one manufacturer of imaging sensors, and if we can sell a lot of them, the price will come down!

I'm no semiconductor engineer, but it seems to me the economics of large sensors are different than most other kinds of chips. In the old days, when you doubled the area of a chip and left the feature size the same, you got a double whammy on cost: you had to pay for twice as much silicon, and the odds that the chip would have a defect doubled, so the chip, before packaging,  became four times as expensive. However, with the ability to map sensor defects and smooth them over in firmware, maybe doubling the area doesn't quadruple the cost.

Maybe someone who knows current fab  and design technology could comment.

Jim

robdickinson

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Re: My take on the Sony Alpha 7/7r
« Reply #34 on: November 13, 2013, 07:13:29 pm »

Canon had a white paper on sensor size and cost of manufacturing but its quite old (1DsmkII era).  I think they said you can fit 20 ff sensors on an 8" wafer and 200 aps-c sized ones. Add in defects hitting those numbers harder and its not surprising ff sensors are more expensive, even given modern methods.

The whitepaper talks of 3 pass etching or ff sensors, they can now do that in one I think.

http://www.robgalbraith.com/images/canon_full-frame_cmos_white_paper.pdf
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hjulenissen

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Re: My take on the Sony Alpha 7/7r
« Reply #35 on: November 14, 2013, 03:05:08 am »

While large sensors will probably always be significantly more expensive than smaller ones (through mechanisms that are well-known in the cpu manufacture process, as well as other mechanisms), this may not matter if the price for sensor is low enough.

$100 vs $1000 would be a big issue for mid-range DSLR cameras.

$1 vs 10$ would probably not be a big issue.

-h
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robdickinson

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Re: My take on the Sony Alpha 7/7r
« Reply #36 on: November 14, 2013, 04:26:10 am »

At the time of that white paper $100 vs $1000 was probably close , possibly more like $100 vs $1500.

Today it may be closer but not that much cheaper.  CPU's get cheaper because they take up less and less silicon as you shrink production.

70D is what $1100 vs $1900 for the 6d. Some of that extra cost with be more profit, some down to more expensive non sensor components ( viewfinder, mirror etc, though no flash etc too). But a big chunk will be the increased sensor cost - say $400+?
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geesbert

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Re: My take on the Sony Alpha 7/7r
« Reply #37 on: November 14, 2013, 05:16:41 am »

I'm afraid people using the high resolution A7R will be disappointed when using their beloved old Leica and Contax wideangles with an adapter. Tolerances are extremely tight here. I'm curious on people actually testing this and reporting.

but as there is now groundglass/pentaprism to align and WYSIWYG is possible with an electronic viewfinder, what's the problem if an adapter is short or long by a bit?
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robdickinson

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Re: My take on the Sony Alpha 7/7r
« Reply #38 on: November 14, 2013, 05:18:08 am »

Its already been tested with Leica wide angle lenses. Anything wider than 35mm has colour shift issues on the A7r.
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Bart_van_der_Wolf

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Re: My take on the Sony Alpha 7/7r
« Reply #39 on: November 14, 2013, 05:45:47 am »

Its already been tested with Leica wide angle lenses. Anything wider than 35mm has colour shift issues on the A7r.

Hi,

Can you share any link to support that, and show what was exactly tested, and whether that produced more Color Cast than other solutions would have done?

Cheers,
Bart
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