resolving power

Started 3 months ago | Discussions
thayes15 Forum Member • Posts: 72
resolving power
1

Hi all

I admit I know nothing about the `resolving power' of a lens. But if it's true that some old lenses have the `resolving power' for a 24 mpix sensor but not a 45 mpix sensor, for instance, has anyone tested this theory?

Has anyone tried an old lens on a smaller and larger mpix sensor and noticed any difference? E.g. the same old lens on a Nikon D850 and a Nikon D610 or the same old lens on a Sony A7 4 and a Sony A7 2?

 thayes15's gear list:thayes15's gear list
Nikon 1 V1 Fujifilm X-E1 Nikon D850 Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 50mm F1.4G +10 more
Nikon D610 Nikon D850 Sony a7
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fferreres Veteran Member • Posts: 4,151
Re: resolving power
2

thayes15 wrote:

Hi all

I admit I know nothing about the `resolving power' of a lens. But if it's true that some old lenses have the `resolving power' for a 24 mpix sensor but not a 45 mpix sensor, for instance, has anyone tested this theory?

Has anyone tried an old lens on a smaller and larger mpix sensor and noticed any difference? E.g. the same old lens on a Nikon D850 and a Nikon D610 or the same old lens on a Sony A7 4 and a Sony A7 2?

It's a bit more complex than that. First, the "resolving power" varies by f-stop, as the more curved outer part of the lens starts to not get used when you stop down. The other is that the "resolving power" is almost invariable much higher in the center than in the corners. This means that in parts of the image, it's resolving much finer detail. Combine both, and it's not clear if it has/doesn't have "resolving power"  at certain resolution, but rather a continuum of gray area responses.

Also, it's a bit hard to define exactly if something is good enough for 24MP or 42 or 60MP sensor. However, it is very true, than one can observe how camera resolves detail in a scene in sensors of increasing resolution. To some extend, this is akin to reading an MTF chart...which varies by f-stop and by distance to the axis. But since we don't have this for most old lenses, we are left with tests.

I too, would like to know how many lenses do under a 60MP sensor. But I won't pay $3500 for such sensor, and may have to wait a few years until price goes significantly down.

OP thayes15 Forum Member • Posts: 72
Re: resolving power

Thanks fferreres

You've educated me. I too will hang for someone who has various sized sensor cameras to check it out!

 thayes15's gear list:thayes15's gear list
Nikon 1 V1 Fujifilm X-E1 Nikon D850 Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 50mm F1.4G +10 more
sensiblename99 Regular Member • Posts: 420
Re: resolving power
2

I have many lenses which I've kept for many years and which I've used on cameras with ever increasing sensor resolution or size, from 1ds2/16.7Mpx, 5D2/21Mpx, A7R2/42Mpx and presently A7r4/61Mpx. So far I'm quite convinced that the concept that some old lenses don't have the resolution for modern sensors is essentially false and my experience is that these higher resolution cameras tend to extract more from older or 'lesser' lenses, just as they do from any modern high resolution lens.

However I agree that a modern lens will be sharper across the frame, with better contrast and allow you to crop further into an image and still get lots of detail, things you might not be able to do with 50 year old lens, but you will still get more out of any lens with a higher res sensor if the final image/print size is the same. A very high res (modern) lens certainly could benefit from a bigger sensor more than an older lens but I'm convinced that an old lens is not made worse.

For the last couple of days I've been using a Canon FL 1.2/58 on an A7R4, the lens is circa 1970 or so, maybe a bit earlier. This lens is really only quite sharp in the central zone and sharpness falls off quite a bit towards the edges but I love the way it renders. It's not a sharp lens by modern standards. I think I'm finding it a 'better' lens on the A7R4 than on the A7R2 simply because I'm not making larger images from it but have a slightly better file from the bigger sensor.

D Cox Forum Pro • Posts: 25,237
Re: resolving power

The question is not whether a lens is good enough for the sensor, but whether a sensor is good enough for the lens. The job of the sensor is to record whatever image is thrown on it. If it can record all the detail in the image, and maybe have resolution to spare, that's fine: we want to see the best that the lens can do.

The problem is more often that the sensor can't record all the fine detail given by a high quality modern lens. Then you get aliasing and moire effects. These can be avoided only by using smaller pixels, or by using film, or by blurring the image with an AA filter.

fferreres Veteran Member • Posts: 4,151
Re: resolving power

D Cox blond hair against very dark background (which is usually...more hwrote:

The question is not whether a lens is good enough for the sensor, but whether a sensor is good enough for the lens. The job of the sensor is to record whatever image is thrown on it. If it can record all the detail in the image, and maybe have resolution to spare, that's fine: we want to see the best that the lens can do.

The problem is more often that the sensor can't record all the fine detail given by a high quality modern lens. Then you get aliasing and moire effects. These can be avoided only by using smaller pixels, or by using film, or by blurring the image with an AA filter.

Great way to put it actually. Like previous post, I think all lenses would benefit, and in this post, succinctly, you argue what is so elusive to many...that some lenses are too sharp for some sensors.False colors became so normal, that I started wondering how other people put up with using a Batis lens in a 24MP body.

I wish Sony would give more attention to Pixel Shift 4x, and that a raw could be synthesized from 4 shots. That using the internal sensors and alignment algorithms, one could do this handheld anytime one was around 1/400.

LoneTree1
LoneTree1 Senior Member • Posts: 2,801
Re: resolving power
1

Resolving power of a lens, if it's diffraction-limited is much higher than you will see out of any current sensor.  Example.  Take a lens that's 50mm focal length and f2.0 aperture.  What is being used to resolve detail is a 25mm aperture which is 50mm /2.   A 50mm lens if it were used at f2 and was perfect would be able to see detail as small as 1/30,000th the frame width since the formula for lens resolution is 116/D which is the lens diameter in mm.  For a 25mm = 4.64 arc seconds.  A 50mm lens gives a scene width in a FF camera of 39 degrees which is 140,000 arc seconds/4.64 means you need a sensor with a resolution of 30,000 pixels wide, or 600 megapixels to achieve full resolution on a FF sensor.  Lens resolution increases proportionally with lens diameter.  Which means, if you have a lens with 2x the aperture (barring any additional aberrations) it would resolve detail 1/2 as small as the smaller aperture lens.  In normal practice, due to lens limitations, a sensor of 300mp would yield maximum lens resolution, in the centre of the image at least.  However, very long focus lenses (f/10-16 given their aperture) can resolve to the diffraction-limit since they have virtually no aberrations if apochromatic.

David Kieltyka
David Kieltyka Veteran Member • Posts: 5,581
Re: resolving power

Right. Sensors outresolving lenses is the ultimate goal. I've seen aliasing artifacts with my Pentax 645z (50mp) and a film-era 45–85/4.5 zoom, so we're not there yet. 

-Dave-

 David Kieltyka's gear list:David Kieltyka's gear list
Leica M9-P Leica M8.2 Pentax 645D Pentax 645Z Panasonic Lumix DMC-GX8 +8 more
OP thayes15 Forum Member • Posts: 72
Re: resolving power

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

 thayes15's gear list:thayes15's gear list
Nikon 1 V1 Fujifilm X-E1 Nikon D850 Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 50mm F1.4G +10 more
LoneTree1
LoneTree1 Senior Member • Posts: 2,801
Re: resolving power

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses.  Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought.  The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer.  Depends on the lens.

fferreres Veteran Member • Posts: 4,151
Re: resolving power

LoneTree1 wrote:

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses. Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought. The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer. Depends on the lens.

It’s a glass half full interpretation though. The new glass is better, but also very different and with other trade offs.

LoneTree1
LoneTree1 Senior Member • Posts: 2,801
Re: resolving power

fferreres wrote:

LoneTree1 wrote:

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses. Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought. The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer. Depends on the lens.

It’s a glass half full interpretation though. The new glass is better, but also very different and with other trade offs.

Control of aberrations should be first.  Everything else should be second.

fferreres Veteran Member • Posts: 4,151
Re: resolving power

LoneTree1 wrote:

fferreres wrote:

LoneTree1 wrote:

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses. Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought. The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer. Depends on the lens.

It’s a glass half full interpretation though. The new glass is better, but also very different and with other trade offs.

Control of aberrations should be first. Everything else should be second.

If you say so....

Rol Lei Nut Veteran Member • Posts: 4,934
Re: resolving power
1

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

You can't just lump all "old lenses" together as though they all perform the same way.

There are huge differences between different "old lenses"...

LoneTree1
LoneTree1 Senior Member • Posts: 2,801
Re: resolving power

fferreres wrote:

LoneTree1 wrote:

fferreres wrote:

LoneTree1 wrote:

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses. Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought. The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer. Depends on the lens.

It’s a glass half full interpretation though. The new glass is better, but also very different and with other trade offs.

Control of aberrations should be first. Everything else should be second.

If you say so....

In this order:

1.  Spherical abberation.

2.  CA, chromatic abberation.

3.  Coma

4.  Distortion

5.  Vignetting

6.  Bokeh

D Cox Forum Pro • Posts: 25,237
Re: resolving power
1

LoneTree1 wrote:

fferreres wrote:

LoneTree1 wrote:

fferreres wrote:

LoneTree1 wrote:

thayes15 wrote:

Man I love science, although my area is more the biological sciences.

When I first decided to take photography seriously as a habit I went back to my school physics notes and re-studied light diffraction through a lens. So much fun, right?

That was awesome input LoneTree1 even though most of it was over my head.

I too like the way some images are rendered with less than perfect lenses. They are more `spiritual' than perfect reproductions.

And I also love images produced crispy sharp as well. Both have their appeal under their own circumstances.

And I love the science involved. It might be that my old lenses don't resolve well enough for the Nikon D850 although I can see now it's way more complex than I thought. But even if they don't resolve as well, maybe that will be the advantage of using an old lens on a large mpix sensor?

Sensors now have enough pixels so they are somewhat intolerant of the aberrations of old lenses. Each time a new, higher-megapixel camera comes out, people say their lenses "aren't as sharp" as they thought. The lenses of course haven't changed and in-fact, may deliver higher resolution than with the lower mp camera, even if at first glance images seem softer. Depends on the lens.

It’s a glass half full interpretation though. The new glass is better, but also very different and with other trade offs.

Control of aberrations should be first. Everything else should be second.

If you say so....

In this order:

1. Spherical abberation.

2. CA, chromatic abberation.

3. Coma

4. Distortion

5. Vignetting

6. Bokeh

Spherical aberration can be a good thing if you want a softer image. Numbers 2 to 4 are always bad. Vignetting is very seldom wanted, and could be added in post.

Bokeh doesn't fit in a list of faults, as it can be nice or nasty.

OP thayes15 Forum Member • Posts: 72
Re: resolving power

Good to know.

I just presumed all new lenses had better resolving power than all old lens - however you define the two things.

 thayes15's gear list:thayes15's gear list
Nikon 1 V1 Fujifilm X-E1 Nikon D850 Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 50mm F1.4G +10 more
Dr_Jon Veteran Member • Posts: 6,469
Re: resolving power

thayes15 wrote:

Hi all

I admit I know nothing about the `resolving power' of a lens. But if it's true that some old lenses have the `resolving power' for a 24 mpix sensor but not a 45 mpix sensor, for instance, has anyone tested this theory?

Has anyone tried an old lens on a smaller and larger mpix sensor and noticed any difference? E.g. the same old lens on a Nikon D850 and a Nikon D610 or the same old lens on a Sony A7 4 and a Sony A7 2?

It's tricky, especially if you're using a smaller sensor on the camera than the lens was designed for, so only using the "better" part of the lens. For example this is shot with my GH5 (which has the pixel density of a c.80MP FF sensor, but only uses the centre quarter of the FF frame) using a 1979 non-L Canon lens (200mm f/4), and I don't see anything to really complain about on the resolving power:

Perhaps more of an issue is nailing focus with old MF lenses, especially with moving targets... as that's the biggest resolution killer...

 Dr_Jon's gear list:Dr_Jon's gear list
Nikon Coolpix 950 Fujifilm FinePix Real 3D W3 Sony RX100 V Canon EOS 5DS R Panasonic GH5 +30 more
OP thayes15 Forum Member • Posts: 72
Re: resolving power

Thanks for posting Dr. Jon
Looks perfectly good to me too. Just got an old nikkor 50mm might compare it with the AFs 1.4G

 thayes15's gear list:thayes15's gear list
Nikon 1 V1 Fujifilm X-E1 Nikon D850 Nikon AF-S Nikkor 14-24mm f/2.8G ED Nikon AF-S Nikkor 50mm F1.4G +10 more
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