Sony a7R II vs III

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Lou Jost
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Post by Lou Jost »

Rik, johny argued that to double the resolution on the sensor without changing m, we'd need a lens with a twice-higher NA. I answered that his alternative of doubling m and stitching also requires a lens with a twice-higher NA to make up for the doubled m.

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Post by rjlittlefield »

Lou Jost wrote:Rik, johny argued that to double the resolution on the sensor without changing m, we'd need a lens with a twice-higher NA. I answered that his alternative of doubling m and stitching also requires a lens with a twice-higher NA to make up for the doubled m.
Um, OK.

But you both wrote "EA", not "NA", and in a preceding sentence JohnnyM specifically wrote that he was concerned about sensor pitch, which to my eye is consistent with worrying about EA.
But with 3,3 pixel pitch divided by 2 = ~ 1,515 pixel pitch what EA would you need?
It's way eazier to get telecentric lens and shoot panorama on higher magnification IMO, also overall faster. Am i wrong?
If you guys are confident that you've been communicating about "NA" instead of the "EA" that was actually written, then I withdraw my comments as irrelevant.

--Rik

Lou Jost
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Post by Lou Jost »

Maybe I don't understand something about the distinction...our discussion was about the difficulty of finding fast enough lenses.

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Post by rjlittlefield »

Lou Jost wrote:Maybe I don't understand something about the distinction...our discussion was about the difficulty of finding fast enough lenses.
I understood it the same way.

From my standpoint, it sounded like you were arguing that a larger coarser pitch sensor presents just the same difficulties as a smaller finer pitch sensor, given the same total number of pixels.

That's a discussion that you and I have had before, and I thought we had finally agreed that indeed the optics have an easier time with the larger sensor. As I wrote to you on 12/9/2016, "Again, the area where I have the most concern is around 1:1 for a 50 megapixel MFT. This is because in that regime a) it seems to be a struggle to get suitable optics on MFT, while b) optics for the FF sensor are still about 1 f-stop less demanding and therefore simpler to acquire and set up. I say "still" because the advantage drops as magnification increases. It is 2 f-stops at m=0, and falls to 0 at m=infinity."

That discussion assumed a single lens in each case, no stitching. In the current discussion, the pano approach has the additional advantage that the lens has to cover a smaller area on the subject, which facilitates having a larger NA even for high magnification.

--Rik

Lou Jost
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Post by Lou Jost »

Yes, I remember that discussion. But here we were keeping physical sensor size constant. The issue was to find the easiest (as in, least time consuming and maybe least expensive) way to double the resolution using that sensor. One way was to use pixel shifting. It was claimed that this would require a lens two stops faster than the lens needed to get the original resolution, and that it would be easier to double the magnification and stitch four frames on the same sensor, without using pixel shifting. I argued that you would still need a lens that is two stops faster to do the stitching, because of the increased m.

I see now that I was implicitly assuming infinity-corrected optics though; finite optics would be slightly different, as you say.

Lou Jost
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Post by Lou Jost »

Macrero, now I think part of the confusion is that the sound the shutter makes depends on several things, such as: is the camera in Live View or not; does the aperture have to stop down during the exposure. So it is possible for people to be misled about what is really going on.

I found this on a Pentax forum about the Pentax KP:
"It's completely silent in Live View mode, if in Manual. The only noise made is if the aperture value changes (example in dark situations would be if you set an aperture other than wide open). The aperture sound is a very faint click.

If you're using it with the OVF then you'll hear the mirror move as the user above stated. In that case you're probably going to use the mechanical shutter anyway as it only makes a bit more noise in addition to the mirror movement."
Read more at: https://www.pentaxforums.com/forums/203 ... z5Ij9dZ031

And here is a review of the K1 Mark ii that is written by someone who seems to be aware of the issues
"Delve into the menus and you’ll find a silent electronic shutter that enables more discreet shooting in live view, although the camera isn’t completely noiseless due to its mechanical aperture operation."

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Post by mjkzz »

Lou Jost wrote: https://blog.kasson.com/the-last-word/f ... -revisted/
Flash is disabled in silent shutter mode in Canon and Nikon.
This blog is kind of odd provided the following assumption/fact: 1 ALL camera shutters move from top to bottom during exposure 2 actually a fact, image on sensor is up side down.

So for Sony, the black band at the top makes sense -- as shutter moves downward, the bottom of the sensor is not exposed because flash is off, so you get a black band at the top of image.

But for Nikon, the black band is at the bottom of image, meaning the top of the sensor was not exposed by flash, so unless triggering mode is rear curtain, this does not make sense.

So I guess the author should have made it clear about test conditions, else, I find the test very confusing.

Of course, the other possibility is Nikon D810 moves shutter bottom up, voiding the first assumption.

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Post by Macrero »

Lou,

that sounds about right, it would be a bit weird if a manufacturer refers to EFCS as "Electronic Shutter" without any further clarifications... But I'm still not sure.

While I wait for Ricoh to reply, I asked the DPR community and this is what I got so far:

"Certainly when you're taking multiple images (e.g. for pixel shift) the mechanical shutter doesn't deploy between exposures, so it can be fully electronic; whether it works that way in all modes is another question.

<edit>

Thinking about the way the mechanics are doing something at the end of a ES exposure in live view, I suspect in most modes it is EFCS."


Btw, I found a thread about stacking at low m with the K-1, I'm afraid it's not very encouraging :(

https://www.pentaxforums.com/forums/6-p ... -d810.html

- Macrero

Edit: I'm on the same boat you was on. I'm trying to decide between the K-1 and the a7R II. Price is pretty much the same, though the a7R II can be purchased for about half of its launch price, while the price of K-1 has not dropped much 2 years after launch.

IQ wise the K-1 is a Nikon D810 with PixelShift, they share the same Sony’s 36MP sensor. The a7R II has a tad newer, higher-resolution, BSI sensor, no mirror, fully e-shutter (though at the expense of 12 bits RAWs), easily adaptable to virtually any lens/bellows, more compact/lighter body.

The only advantage of the K-1 is the PixelShift and maybe 14 bits RAWs with e-shutter (not sure about this one).
https://500px.com/macrero - Amateurs worry about equipment, Pros worry about money, Masters worry about Light

Lou Jost
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Post by Lou Jost »

That does sound grim. I've been reading a lot on that Pentax forum lately, and many of the posters seem to be defensive fanboys who ignorantly attack anybody who criticizes a feature of a Pentax lens or camera. Just reading that thread made me cringe, and there are many others like it. Michael Erlewine was remarkably calm about all the sniping and condescending advice he got in response to his perfectly reasonable post.

I think I can handle the inconvenience of the constant screen brightness. Something similar happens in Olympus sometimes, so I am used to it. I just take a test exposure by trial and error to eventually get the right exposure. It only takes a few seconds.

I had already bought the camera, it is waiting for me in the US, and if I can't manage it I'll trade it for the A7Rii. But I will miss that pixel shift feature (unless it doesn't work, but Michael seemed to want to keep the camera and seemed to like it for pixel shift).

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Post by Macrero »

Yeah, it's shameful, but that's a typical behavior of fan (fanatic) boys. I just ignore those replies...

Well, I'm not in hurry to get a new camera, so I will wait for you to test the K-1 and share your impressions about it before making a decision.
https://500px.com/macrero - Amateurs worry about equipment, Pros worry about money, Masters worry about Light

Lou Jost
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Post by Lou Jost »

I'll let you know just a few days from now.

Macrero
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Post by Macrero »

Nice, thanks!
https://500px.com/macrero - Amateurs worry about equipment, Pros worry about money, Masters worry about Light

Macrero
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Post by Macrero »

Lou,

I'm trying to find out if there's a way to batch-process a stack shoot with the K-1 in PixelShift, but I can't find anything about either Pentax or Sony :? Do you know if it possible and what software will do that? If there is no way, that would be a huge drawback for stacking :(

Btw, looking into that I found out that Michael Erlewine moved to Sony (a7R III):

https://forum.luminous-landscape.com/in ... c=121740.0
https://500px.com/macrero - Amateurs worry about equipment, Pros worry about money, Masters worry about Light

Lou Jost
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Post by Lou Jost »

I hadn't though of that batch-processing problem. But I think one could make a simple work-around for that, using a macro recording program. Record the keystrokes needed to make the first conversion, and then play it back until done. Using this technique, anything can be batch-processed.

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Post by JohnyM »

Somehow fresh info about A7RIII shifting:
https://www.dpreview.com/news/140315455 ... in-a7r-lll

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