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03-21-2015, 06:38 PM   #16
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QuoteOriginally posted by rawr Quote
Just for info, a related Pentax patent from 2007. But it seems everyone - Panasonic, Nikon etc - has patents on this sort of stuff.
Thanks, I was looking for that - having just a vague recollection that Pentax had a patent on something related.
This part is interesting: "the electroluminescent display displays at least the object image captured by the image pickup device"; so, not just some super-imposed information but a hybrid viewfinder.

kadajawi, it doesn't have to be any of the commercial displays currently on sale

03-21-2015, 07:21 PM   #17
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QuoteOriginally posted by rawr Quote
That's the basic problem with any 'super OVF' with EVF elements. Essentially they need to merge two viewscreens (digital and optical) without any IQ or other compromises. No one has got it completely right yet, I think.
Pentax seems to have that already. Look at the AF point indicator. That is essentially a screen that, when on, overlays itself into the OVF image. It is a light shining through a mirror. The problem is that there seems to be not enough space to fit a screen that is big enough. That seems to be the main hurdle.

Fuji is doing a similar thing, they too are using a prism to merge the two images, and when you block out the light coming from outside you get an EVF. I think it might be possible to do the same using the already existing pentaprism, alternatively a similar system could be employed by inserting another prism into the light path.

@Kunzite: I was looking at prototypes shown by Samsung or LG a few years back. Or are you aware of OLED screens that are fully transparent AND high res? If the transparency is achieved by wide gaps between the pixel it won't help, you couldn't get the resolution that is needed.
03-21-2015, 07:53 PM - 1 Like   #18
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I don't know how feasible such a viewfinder is, but it seems to me that it would be a benefit for everyone if it could be done. At the simplest level, it would make live view accessible through the viewfinder.

If Ricoh can combine this with their recent patent for the variably transparent mirror, it could be even better. Having access to the sensor's readout while the image is viewable in the OVF would render a number of components redundant.

1. The metering sensor would no longer be needed. Image sensors provide this information to the processor in more detail anyway.
2. If the sensor has PDAF capability, the separate AF sensor could be removed. That separation is the cause of front/back focus issues. The argument that on-sensor AF is slower or less capable of tracking is valid, but getting less so with every generation of camera.
3. If the mirror no longer had to move up out of the way, none of the mechanical apparatus to do that would be needed.
4. There would be less calibration work needed for production and repair.

The result would be a camera that was simpler, more robust and eventually cheaper. Having removed all that gear, you could put in a bigger battery if you wanted to get closer to the battery life of a DSLR.

I don't get the point about the sensor overheating and creating image noise. My K-01 doesn't suffer from this and most mirrorless cameras don't have an issue. I suppose it might depend on the specific sensor used.

I any case, I hope Ricoh is researching all of this and I trust them to make sound decisions for us photographers, because they almost always do.
03-21-2015, 08:13 PM   #19
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QuoteOriginally posted by JPT Quote
I don't know how feasible such a viewfinder is, but it seems to me that it would be a benefit for everyone if it could be done. At the simplest level, it would make live view accessible through the viewfinder.

If Ricoh can combine this with their recent patent for the variably transparent mirror, it could be even better. Having access to the sensor's readout while the image is viewable in the OVF would render a number of components redundant.

1. The metering sensor would no longer be needed. Image sensors provide this information to the processor in more detail anyway.
2. If the sensor has PDAF capability, the separate AF sensor could be removed. That separation is the cause of front/back focus issues. The argument that on-sensor AF is slower or less capable of tracking is valid, but getting less so with every generation of camera.
3. If the mirror no longer had to move up out of the way, none of the mechanical apparatus to do that would be needed.
4. There would be less calibration work needed for production and repair.

The result would be a camera that was simpler, more robust and eventually cheaper. Having removed all that gear, you could put in a bigger battery if you wanted to get closer to the battery life of a DSLR.

I don't get the point about the sensor overheating and creating image noise. My K-01 doesn't suffer from this and most mirrorless cameras don't have an issue. I suppose it might depend on the specific sensor used.

I any case, I hope Ricoh is researching all of this and I trust them to make sound decisions for us photographers, because they almost always do.
1. The metering sensor should have a huge DR, far beyond what the sensor can do. How else is it able to meter between bright daylight and virtually no light at all?

2. Behind the main mirror there is one that goes to the AF sensor. The dedicated AF sensor seems much more light sensitive thanks to a bigger AF sensor. Can't do that with on sensor PDAF.

The main usage for the transparent mirror is IMHO to be able to either give the AF sensor more light, or the OVF. The camera can automatically switch between great low ligh focusing and a really bright OVF, as if it were designed before AF was introduced.

03-21-2015, 08:17 PM   #20
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Nikon does a hybrid display with their dSLRs. The focus points, AF markings and (on FF models) crop margins are projected onto the focus screen image.


Steve
03-21-2015, 08:52 PM   #21
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QuoteOriginally posted by kadajawi Quote
Can't do that with on sensor PDAF.
But there are many mirrorless that do AF down to -4 EV (Panasonic GH4, GX7, GM1, GM5; Samsung NX-1; Sony A7s), which exceeds any OVF DSLR at the moment (even the K-3's -3EV). Some mirrorless (eg the A7s) can also meter down to -3EV, just like the K-3.

So on sensor PDAF need not always have light limitations.
03-22-2015, 03:09 AM   #22
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QuoteOriginally posted by kadajawi Quote
@Kunzite: I was looking at prototypes shown by Samsung or LG a few years back. Or are you aware of OLED screens that are fully transparent AND high res? If the transparency is achieved by wide gaps between the pixel it won't help, you couldn't get the resolution that is needed.
It doesn't have to be solved today (or this year)
The pixel density could be lower than the one in a typical EVF panel, because the screen would be larger.
03-22-2015, 05:14 AM   #23
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QuoteOriginally posted by stevebrot Quote
Nikon does a hybrid display with their dSLRs. The focus points, AF markings and (on FF models) crop margins are projected onto the focus screen image.

Steve
That's not exactly a hybrid display... you might as well attach a powered drill to your wheel and call it a hybrid. Don't they, like Canon, use a black/transparent LCD screen that can be activated when wanted? With pre-defined segments? You can't display images on it. IIRC their display doesn't light up either. If anything their tech, if dark enough, could be used together with the pentaprism attached monitor to have the review function in screen work without having to mechanically move the mirror up. But I am always wary of things that can make the OVF darker, that's a trade off I don't want, and I think OVF fans in general wouldn't want to accept. OVFs are already dim enough.

QuoteOriginally posted by rawr Quote
But there are many mirrorless that do AF down to -4 EV (Panasonic GH4, GX7, GM1, GM5; Samsung NX-1; Sony A7s), which exceeds any OVF DSLR at the moment (even the K-3's -3EV). Some mirrorless (eg the A7s) can also meter down to -3EV, just like the K-3.

So on sensor PDAF need not always have light limitations.
Thanks. Wasn't aware of that, I thought in low light the mirrorless cameras have more problems than DSLRs. Though by using a mirror that can adjust translucency on the fly DSLRs could go much further. If 1/3 of the light is let through to the AF sensor, imagine what happens if you let 2/3 to the AF sensor in moments of need. You can't boost sensitivity like that in a mirrorless.

QuoteOriginally posted by Kunzite Quote
It doesn't have to be solved today (or this year)
The pixel density could be lower than the one in a typical EVF panel, because the screen would be larger.
True, but the pixel density would still be high.

Transparent OLED Displays
The 2011 Samsung prototype had 14", 940x540 and a transmissivity of 40%. And in 2014 LG had an 18" screen that had a 30 percent transmittance. We are many years away from having an OLED screen that is transparent enough, and LCD screens aren't that great either (in addition to the need of backlighting).

Though if you use OLED you could use a rollable OLED display that can be rolled into position... it wouldn't take up as much space. Or there might even be enough space to move it into the light path when needed. But overlays are impossible (maybe the bottom status display/histogram could be done by not moving the display fully out of view).


This is what Fuji is doing.



Another Nikon patent, similar to what Kunzite describes:
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First of all Nikon has a patent on that, and secondly the technology needed to make that work does not exist at this point, nor may it ever (within a reasonable time frame).

I wonder... the position of the pentaprism isn't fixed, is it? It could be moved up a bit, say a few mm. Because then you could have a bigger screen placed in the front of the pentaprism, there'd be enough space for a prism to redirect the light. The whole thing would have to be a marvel in packaging and optical design, but this is Pentax. If anyone can do it...

03-22-2015, 07:25 PM   #24
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I think we will probably end up with something like this as camera makers try and feed more data into our optical path:


[f-35 hemet mounted display - cheap at about $750,000. Creative Commons license]
03-23-2015, 01:33 AM   #25
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That F-35 helmet is bullshit. Together with the new oversized seat pilots can't look behind them. Good luck when doing a dogfight... this plane can't do it/is completely rubbish at it.

Obviously I don't want the camera to turn into that monster, though an Samsung VR Gear or so like attachment/support could eventually be nice. Put on a helmet with the smartphone inside it, and have that in front of your camera.

The overlays that I think the camera could have are user adjustable, and you can have as many or little as you want... and they can differ from user mode to user mode.

The idea is to give flexibility and choice to those who need/want it. Having a good histogram that shows the DR of the scene and tells you what the camera is able to capture in a raw file would be pretty valuable. Having the ability to switch to EVF and have focus peaking and a zoomed in view would be. etc.

Obviously features shouldn't be there just for the sake of it, they should make sense to photographers, at least some. Otherwise it won't be a Pentax.
03-23-2015, 02:11 AM   #26
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Wait, you're all discussing how it can be done, but do we really want it? OVF and EVF both have their own advantages and disadvantages. Merging them into one seems to create a hybrid that has the disadvantages of both.

OVF with EVF overlay:
- OVF means realtime speed, but then the EVF part will be in the way of that.
- EVF means a bright viewfinder... Not so if you depend on the OVF part to show what's in front of the lens.
- EVF means the VF will be independant on the sensor format. (With an EVF, an APSC camer could sport an FF format viewfinder.) Introduce a OVF part into that and it's gone again.
- Battery life of DSLRs is above excellent, not so anymore if there's an EVF added on top.
- An EVF means no more manual calibrations of mirror, mechanisms, focussing screens and VF optics. Reducing a LOT of costs... untill you nerf that again with an OVF part.
- I won't even explain the obvious size advantages that would get nerfed.
- As you guys seem to thave discoverd, it's an engineering nightmare, which translates into to extra costs.

At the same time, I enjoy best of both worlds right now. We're enthusiasts. We're bound to have multiple bodies anyway. Even if only because we upgrade and can't let go of the old ones. The two technologies can easily coexist next to eachother. All we really need is an excellent way of using the same lenses on both technologies.

Last edited by Clavius; 03-23-2015 at 02:17 AM.
03-23-2015, 04:06 AM   #27
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I disagree with some of that. The EVF overlay would just give additional information like histogram from the light meter (real time not needed) and the kind of information we already have... aperture, focus point indicator... maybe add flexible guide lines, a way to display different aspect ratios etc. It wouldn't be able to open up a box that shows a zoomed in view. And after the shot a way to review the image without having to try to see the LCD screen under bright sunlight.

If you switch to the live view mode you get a bright EVF, with all the advantages of an EVF.

Larger screen than mirror might be done, hopefully it will be.

Personally I only use two bodies... my K-5 and my smartphone. I do not want to carry an additional camera. A slight size and weight gain is better (to me) than another body.

Your size advantage of mirrorless would be seriously hurt if you want to use the same mount as a DSLR, unless you go the adapter route.

For the most part it seems pretty straight forward from an engineering standpoint. Either you manage to create a bit more space for a larger screen and optics to fit where the AF point indicator currently is, or you go the Fujitsu route and add a screen and prism after the big pentaprism. I'd put the screen close to the flash, the optics needed there seem smaller and it would just result in a somewhat bigger hump.

This tech could be the future of the DSLR, a way to keep it relevant next mirrorless.

Last edited by kadajawi; 03-23-2015 at 04:11 AM.
03-25-2015, 05:34 AM   #28
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QuoteOriginally posted by kadajawi Quote
If you switch to the live view mode you get a bright EVF, with all the advantages of an EVF.
...without the size advantage. And without the shortened registry distance. So, "all of the advantages" is a bit of stretch.

QuoteOriginally posted by kadajawi Quote
Your size advantage of mirrorless would be seriously hurt if you want to use the same mount as a DSLR, unless you go the adapter route.
Yes, a good adapter of course.


QuoteOriginally posted by kadajawi Quote
This tech could be the future of the DSLR, a way to keep it relevant next mirrorless.
It's a bit sad if the OVF requires the addition of an EVF to keep it viable. I don't think that's necessary at all.
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