Sony's new curved sensor - this is a big deal

Started 3 months ago | Discussions
jeffcpix
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Re: Sony's new curved sensor - this is a big deal
In reply to brownie314, 3 months ago

It might not be for the interchangeable lens crowd -- or even the fixed lens high end market.

Most consumers seem perfectly happy with their cell phone cameras. Give them a UWA and a high res sensor and they'd be happy to crop instead of zoom. Tiny lenses whose focus can change by the application of an electric charge but lack flat field correction might be a great combination for a concave sensor.

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Dave Lively
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Worthless for interchangeable lens cameras, great for cell phones
In reply to brownie314, 3 months ago

This is huge new for cell phone makers.  They can use a simpler lens with a curved sensor and maintain quality.  Since the lens no longer needs to be telecentric it should be possible to make the lens + sensor combination thinner which is very important for cell phones.  You cannot have a curved sensor and image stabilization but most cell phones do not have IS now so that will not be a loss.

Dedicated cameras with a fixed lens should benefit too although the loss of image stabilization would be a  problem for many users.  But the ability to have better optical quality with a simpler and thinner lens would be a big plus for many users.

For cameras with interchangeable lenses a curved sensor makes little sense.  The best curve varies by focal length so any chosen curve would be a compromise.  No existing lenses could be used and not having image stabilization would be a big drawback for many buyers.  Since SLR lenses have to be somewhat telecentric to leave enough space for the mirror there would be much less potential benefit for SLRs than there would be for mirrorless and fixed lens cameras.

If I was in the market for a $3000 FF camera with a permanently attached lens like the Sony RX1 this would be big news.  For the sort of cameras I am actually likely to buy, not so much.  I do use my cell phone when I do not have real camera though and they need all the help they can get.  But I have a hard time getting excited about the cameras in cell phones.

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GodSpeaks
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No it's not
In reply to brownie314, 3 months ago

Any lens mated to a curved sensor MUST be designed for that sensor.

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webrunner5
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Re: No it's not
In reply to GodSpeaks, 3 months ago

There was a thread somewhere on this site that had a link to some testing site that pretty much stated that most "Film Era" legacy lenses were pretty bad performers on modern day digital cameras. And they had tons of example pictures and lenses they tested. And most has to do to to the rear lens element on old stuff. Even coating and amazingly the thickness of the glass in front of the sensor. I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front. The thicker the glass the worse old lenses do. YMMV.

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brownie314
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Re: Worthless for interchangeable lens cameras, great for cell phones
In reply to Dave Lively, 3 months ago

Dave Lively wrote:

This is huge new for cell phone makers. They can use a simpler lens with a curved sensor and maintain quality. Since the lens no longer needs to be telecentric it should be possible to make the lens + sensor combination thinner which is very important for cell phones. You cannot have a curved sensor and image stabilization but most cell phones do not have IS now so that will not be a loss.

Dedicated cameras with a fixed lens should benefit too although the loss of image stabilization would be a problem for many users. But the ability to have better optical quality with a simpler and thinner lens would be a big plus for many users.

For cameras with interchangeable lenses a curved sensor makes little sense. The best curve varies by focal length so any chosen curve would be a compromise. No existing lenses could be used and not having image stabilization would be a big drawback for many buyers. Since SLR lenses have to be somewhat telecentric to leave enough space for the mirror there would be much less potential benefit for SLRs than there would be for mirrorless and fixed lens cameras.

If I was in the market for a $3000 FF camera with a permanently attached lens like the Sony RX1 this would be big news. For the sort of cameras I am actually likely to buy, not so much. I do use my cell phone when I do not have real camera though and they need all the help they can get. But I have a hard time getting excited about the cameras in cell phones.

"For cameras with interchangeable lenses a curved sensor makes little sense. The best curve varies by focal length so any chosen curve would be a compromise."

I disagree.  A flat sensor is a curve too.  Why is a flat sensor the best "curve" for a sensor in any system?  Yes, you would have to choose your curve to be a compromise between all focal lengths.  But I am guessing that if optical designers had a choice, many years ago as to what shape to make the sensor (or film) it would not have been flat.  Flat was chosen for other, non-optical reasons.

And yes, it might make legacy lenses obsolete.  Trailblazing technology often does this.

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Hen3ry
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Curved sensor - wide vs tele - Ricoh GR style design?
In reply to brownie314, 3 months ago

I think it is the Ricoh GR, where you can change the lens or the sensor or both?

Why not have sensor changes for maximum IQ with the sensors matching the lenses?

Think about architectural photography, commercial photography, landscape …

Wow!

Cheers, geoff

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stevo23
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Re: Sony's new curved sensor - this is a big deal
In reply to Stephan K, 3 months ago

Stephan K wrote:

On the one hand a curved sensor should be compatible with existing lenses, as the curve matches most lens's convex field curvature, and should produce sharper edges as a result. On the other hand, each focal length and each field curvature would have it's own optimum sensor curvature, so amount of sensor curvature would be a compromise, but still better than flat sensor. Added edge sharpness would be for 2 reasons: better fit to field curvature, and incident light angle closer

to 90 degrees at edges.

"Normal to the plane" is the correct term. Ha ha.

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meland
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Re: No it's not
In reply to webrunner5, 3 months ago

webrunner5 wrote:

There was a thread somewhere on this site that had a link to some testing site that pretty much stated that most "Film Era" legacy lenses were pretty bad performers on modern day digital cameras. And they had tons of example pictures and lenses they tested. And most has to do to to the rear lens element on old stuff. Even coating and amazingly the thickness of the glass in front of the sensor. I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front. The thicker the glass the worse old lenses do. YMMV.

One of the issues is that digital sensors (or the IR / anti aliasing filters mounted on the surface of the sensor) tend to be very reflective. So lenses designed for digital, as opposed to film, often have a rear element and/or baffling which is designed to prevent reflected light from the sensor being directed back into the lens which causes flare or a loss of contrast.

But I think you may have got your measurements wrong (a missing decimal point perhaps?) in your comment "I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front."

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alanr0
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Filter stack on digital sensors
In reply to meland, 3 months ago

meland wrote:

webrunner5 wrote:

There was a thread somewhere on this site that had a link to some testing site that pretty much stated that most "Film Era" legacy lenses were pretty bad performers on modern day digital cameras. And they had tons of example pictures and lenses they tested. And most has to do to to the rear lens element on old stuff. Even coating and amazingly the thickness of the glass in front of the sensor. I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front. The thicker the glass the worse old lenses do. YMMV.

One of the issues is that digital sensors (or the IR / anti aliasing filters mounted on the surface of the sensor) tend to be very reflective. So lenses designed for digital, as opposed to film, often have a rear element and/or baffling which is designed to prevent reflected light from the sensor being directed back into the lens which causes flare or a loss of contrast.

But I think you may have got your measurements wrong (a missing decimal point perhaps?) in your comment "I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front."

Roger Cicala of Lensrentals blogged about this.

DPR thread here.  Around 1mm for Leica and 4 mm for m4/2 is what was reported, along with a set of MTF measurements.

Cheers.

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stevo23
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Re: Sony's new curved sensor - this is a big deal
In reply to peevee1, 3 months ago

peevee1 wrote:

stevo23 wrote:

peevee1 wrote:

stevo23 wrote:

peevee1 wrote:

MoreorLess wrote:

brownie314 wrote:

MoreorLess wrote:

brownie314 wrote:

If Sony can get it right (make it manufacturer at a "reasonable" price) this could be a game changer bigger than all of this mirrorless stuff (actually, many of will argue that mirrorless wasn't really a game changer - but that is another topic).

This has the potential to make it possible to put really small, simple lens designs on bodies and have IQ on par with the most expensive glass available.

I'd guess the big issue maybe that sensors and lenses need to be matched together to make such a system work, indeed I could potentially even see zooms causing issues. That Sony didn't look to use this sensor with there own FF mirrorless system does tend to suggest there maybe problems.

I spose if sensors really started to come down in price it also made lens design cheaper then it might make sense to create a system like the Ricoh GXR with linked sensor/lens units.

Yes, I agree that it would have little benefit for longer lenses - and may cause significant problems.

But I was thinking more along the lines of a compact non-interchangeable lens camera - like the RX1. With a curved sensor and wide angle lens - this could be a small body but spectacular performer. We will see. The rumor going around right now is that the RX2 will have curved sensor and a 35mm f/1.8 lens. Seems interesting.

Realistically though the RX1 was already a very good performer here, certainly much better than the FE 35mm 2.8.

Its not mentioned much but if you look at the RX1 len internals you can see a massive rear element...

I'm guessing that having that big chuck of glass near to the sensor allows for correcting light angles much more than can be achieved with interchangeable lenses.

A slightly faster, slightly smaller lens would be a benefit to the RX2 although I think improved AF and a built in viewfinder would be bigger improvements.

Actually, large rear element close to sensor potentially causes more problems with vignetting and color shifts than a small one would.

why?

Draw a picture. Put a line of light from every corner of the lens to every corner of the sensor. You'll see.

And...I see that it actually improves things.

You don't see sharper angles of light from the opposite size of the lens?

I don't know that it's necessarily true as you're visualizing it. Having a larger rear element can actually reduce that problem, especially if the lens is designed for it.

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stevo23
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Re: Sony's new curved sensor - this is a big deal
In reply to meland, 3 months ago

meland wrote:

stevo23 wrote:

jcharding wrote:

Well, if implemented fully (by Sony and whomever Sony sells the sensor too) it could also mean that all legacy lenses become useless.

I don't think so. My understanding at this early stage is that the amount of correction is merely in line with the current curvature of today's lenses. Lenses aren't flat today and a slight curve would benefit them.

Ah, but the amount of curvature, i.e. the deviation from having a perfect flat field is certainly not consistent with today's lenses. Most camera lenses are computed to give as close as possible to a flat field at the film / sensor plane for obvious reasons, even if they don't always achieve it. A curved sensor in an interchangeable lens camera 'might' just just give better results by pure coincidence in matching the curve of the sensor with the curved field of one or two less than perfect lenses but it is highly unlikely to do so with most. And of course that is assuming that the field curvature will always be towards the lens when for some lenses it actually curves the other way.

All lenses have field curvature. Some more and some less. The goal is flatness, but it's impossible to achieve. What we don't know is how much is typical and how much this sensor has. Nor have we been told definitively that this will require all new lenses. We have been told that it will allow for simpler designs.

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brownie314
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Re: Sony's new curved sensor - this is a big deal
In reply to stevo23, 3 months ago

stevo23 wrote:

meland wrote:

stevo23 wrote:

jcharding wrote:

Well, if implemented fully (by Sony and whomever Sony sells the sensor too) it could also mean that all legacy lenses become useless.

I don't think so. My understanding at this early stage is that the amount of correction is merely in line with the current curvature of today's lenses. Lenses aren't flat today and a slight curve would benefit them.

Ah, but the amount of curvature, i.e. the deviation from having a perfect flat field is certainly not consistent with today's lenses. Most camera lenses are computed to give as close as possible to a flat field at the film / sensor plane for obvious reasons, even if they don't always achieve it. A curved sensor in an interchangeable lens camera 'might' just just give better results by pure coincidence in matching the curve of the sensor with the curved field of one or two less than perfect lenses but it is highly unlikely to do so with most. And of course that is assuming that the field curvature will always be towards the lens when for some lenses it actually curves the other way.

All lenses have field curvature. Some more and some less. The goal is flatness, but it's impossible to achieve. What we don't know is how much is typical and how much this sensor has. Nor have we been told definitively that this will require all new lenses. We have been told that it will allow for simpler designs.

Right - the goal is flatness - because the sensor is flat - that is the only reason.  Yes - the point is simpler lens designs with fewer elements.  I think the best use of this curved sensor initially will be in fixed lens primes cameras - like the RX1, or Fuji x100s.  Could allow for very fast lenses in small packages.

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stevo23
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Re: Sony's new curved sensor - this is a big deal
In reply to eyeswideshut, 3 months ago

eyeswideshut wrote:

ray s james wrote:

I agree with stev023, the opposite should be true, especially regarding old lenses.

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Ray

Afraid not. Curvature of the sensor will allow simpler lens designs but wreak havoc with legacy lenses designed for a flat field sensor.

I don't know why - legacy lenses are anything but flat. We don't know how much curve is in this new sensor and we don't know how flat lenses really are other than the fact that they aren't flat. Flat is the goal, but flat they are not.

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meland
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Re: Filter stack on digital sensors
In reply to alanr0, 3 months ago

alanr0 wrote:

meland wrote:

webrunner5 wrote:

There was a thread somewhere on this site that had a link to some testing site that pretty much stated that most "Film Era" legacy lenses were pretty bad performers on modern day digital cameras. And they had tons of example pictures and lenses they tested. And most has to do to to the rear lens element on old stuff. Even coating and amazingly the thickness of the glass in front of the sensor. I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front. The thicker the glass the worse old lenses do. YMMV.

One of the issues is that digital sensors (or the IR / anti aliasing filters mounted on the surface of the sensor) tend to be very reflective. So lenses designed for digital, as opposed to film, often have a rear element and/or baffling which is designed to prevent reflected light from the sensor being directed back into the lens which causes flare or a loss of contrast.

But I think you may have got your measurements wrong (a missing decimal point perhaps?) in your comment "I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front."

Roger Cicala of Lensrentals blogged about this.

DPR thread here. Around 1mm for Leica and 4 mm for m4/2 is what was reported, along with a set of MTF measurements.

Cheers.

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Alan Robinson

That's very interesting!  Thanks for the links.

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Stephan K
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Re: Sony's new curved sensor - this is a big deal
In reply to stevo23, 3 months ago

stevo23 wrote:

Stephan K wrote:

On the one hand a curved sensor should be compatible with existing lenses, as the curve matches most lens's convex field curvature, and should produce sharper edges as a result. On the other hand, each focal length and each field curvature would have it's own optimum sensor curvature, so amount of sensor curvature would be a compromise, but still better than flat sensor. Added edge sharpness would be for 2 reasons: better fit to field curvature, and incident light angle closer

to 90 degrees at edges.

"Normal to the plane" is the correct term. Ha ha.

Very good, Stevo. English is my 3rd language, you want to carry on the discussion in Afrikaans or German?

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alanr0
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How curved?
In reply to stevo23, 3 months ago

stevo23 wrote:

eyeswideshut wrote:

ray s james wrote:

I agree with stev023, the opposite should be true, especially regarding old lenses.

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Ray

Afraid not. Curvature of the sensor will allow simpler lens designs but wreak havoc with legacy lenses designed for a flat field sensor.

I don't know why - legacy lenses are anything but flat. We don't know how much curve is in this new sensor and we don't know how flat lenses really are other than the fact that they aren't flat. Flat is the goal, but flat they are not.

If we refer back to the photoblographer article you linked to earlier we can make an estimate.

One of the touted advantages is that rays from the centre of the lens strike the sensor at close to normal incidence. For a simple lens, that puts the centre of curvature at the rear nodal point of the lens. The radius of curvature of the sensor must be close to 35 mm for the 35 mm f:1.8 lens mentioned.

At the edge of the 24 x 36 mm frame, 18 mm off-axis, the height of the sensor will be 3.9 mm above the centre.

At f:1.8, this gives a circle of confusion 2.2 mm in diameter. You won't get very sharp results with a lens designed for a flat field.

HTH

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Stephan K
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Re: How curved?
In reply to alanr0, 3 months ago

My guess is that because the majority of (legacy and newer) lenses have convex field curvatures, a curved lens will generally produce significantly better results even with existing lenses, in addition to the advantage of less acute light angles at the sensor edge for all lenses, more so for wide angle lenses.

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stevo23
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Re: Sony's new curved sensor - this is a big deal
In reply to Stephan K, 3 months ago

Stephan K wrote:

stevo23 wrote:

Stephan K wrote:

On the one hand a curved sensor should be compatible with existing lenses, as the curve matches most lens's convex field curvature, and should produce sharper edges as a result. On the other hand, each focal length and each field curvature would have it's own optimum sensor curvature, so amount of sensor curvature would be a compromise, but still better than flat sensor. Added edge sharpness would be for 2 reasons: better fit to field curvature, and incident light angle closer

to 90 degrees at edges.

"Normal to the plane" is the correct term. Ha ha.

Very good, Stevo. English is my 3rd language, you want to carry on the discussion in Afrikaans or German?

My Afrikaans is kind of weak and my German is as good as my Arabic...

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stevo23
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Re: How curved?
In reply to alanr0, 3 months ago

alanr0 wrote:

stevo23 wrote:

eyeswideshut wrote:

ray s james wrote:

I agree with stev023, the opposite should be true, especially regarding old lenses.

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Ray

Afraid not. Curvature of the sensor will allow simpler lens designs but wreak havoc with legacy lenses designed for a flat field sensor.

I don't know why - legacy lenses are anything but flat. We don't know how much curve is in this new sensor and we don't know how flat lenses really are other than the fact that they aren't flat. Flat is the goal, but flat they are not.

If we refer back to the photoblographer article you linked to earlier we can make an estimate.

One of the touted advantages is that rays from the centre of the lens strike the sensor at close to normal incidence. For a simple lens, that puts the centre of curvature at the rear nodal point of the lens. The radius of curvature of the sensor must be close to 35 mm for the 35 mm f:1.8 lens mentioned.

? How is this known?

At the edge of the 24 x 36 mm frame, 18 mm off-axis, the height of the sensor will be 3.9 mm above the centre.

? What am I missing?

At f:1.8, this gives a circle of confusion 2.2 mm in diameter. You won't get very sharp results with a lens designed for a flat field.

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peevee1
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Re: No it's not
In reply to webrunner5, 3 months ago

webrunner5 wrote:

There was a thread somewhere on this site that had a link to some testing site that pretty much stated that most "Film Era" legacy lenses were pretty bad performers on modern day digital cameras. And they had tons of example pictures and lenses they tested. And most has to do to to the rear lens element on old stuff. Even coating and amazingly the thickness of the glass in front of the sensor. I remember a Leica sensor has a 1mm thick glass and m4/3 has 4mm glass in front. The thicker the glass the worse old lenses do. YMMV.

4mm? It is VERY hard to believe, especially on cameras with IBIS. Maybe Pana. IBIS must be really strong to handle that weight.

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