[myrdinn]

I was thinking about the limits that we might meet by using old lenses on new camera's.

Modern camera's have more pixels than old camera's. Does that mean that modern camera's need better lenses? In other words: does a lens have a maximum resolution that it can handle, or that is is designed for? Is it possible that sometimes the resolution of a modern camera is higher than the resolution of an old or a cheap lens?

My question arose while I was thinking about the old lenses, that can still be used on the newest Pentax camera's. The old lenses were created for the traditional, analog, photography using pellicule. Old fashioned films (like colour slides) had - if I'm right - a resolution of maximum 18 million pixels, very often less and no more than 16 million pixels. So I suppose that for a camera company it would have been a waste of the money to create lenses that could produce a much higher resolution.
Let's suppose that for their best lenses they were looking for a resolution of about 20 million pixels, and for their cheapest lenses 15-16 milliion pixels. If that is true, the best 'analog' lenses are still perfect for a camera like the K5 but the cheap lenses might already cause problems. Don't forget that the Pentax engineers redesigned the 18-55 mm lens when they introduced the first 14 millions Pentax camera, just because the old verison of the lens wasn't good enough for that new camera.
What happens if new camera's get a much higher resolution like the newest Sony chip with its 24 million pixels? Can we then still use our old lenses? Or will they not be good enough anymore to be used?

Is my way of thinking right or am I just worrying about nothing?

[westmill]

Wow ! Not that simple... but basicly correct.... any camera is only as good as the glass you put in front of it.
A cheaper lesser camera will give superior results with a top lens to a top end camera with cheap glass !

[hcc]

+1
"Good glass is worth every penny" / "A lens is an investment"

A good lens make a huge different to your photograph IQ independently of the camera body. Pentax in particular has a wide range of superb older prime lenses, ans any Pentax users should take full advantage of these legacy lenses.

[myrdinn]

+1
"Good glass is worth every penny" / "A lens is an investment"

A good lens make a huge different to your photograph IQ independently of the camera body. Pentax in particular has a wide range of superb older prime lenses, ans any Pentax users should take full advantage of these legacy lenses.

That's the question. Will the old lenses - produced for analog films with a limited resolution of 16 million pixels - still be good enough for the newest generations of camera's?

[jatrax]

I think the OP was concerned that legacy glass might not work on newer sensors (24mp plus). And by legacy I mean any lens designed for film or for a digital sensor in say the 10mp range.

I think this has been discussed several times here and with differing opinions. I am certainly not qualified to give an educated answer.

The most scientific answer I see in the other thread is that even at 24mp we are still a long way from approaching the resolution of our glass.

Here is a link to the discussion if you want to check it out. The conclusion was that current, good, glass can resolve enough for at least a 300mp sensor.

[bdparker]

Agree with Westmill
Try not to confuse yourself here, it difficult to define a lens in pixel resolution when it is purely analogue, glass is glass, hold it up to your eye you will see the same thing your camera sees. The camera is only the means of capturing the image coming through the lens (in raw terms).

So a cheap lens in most cases will produce a poor quality image compared to a well constructed lens. And like hcc said, their are some good quality old Pentax lenses around that will still produce good quality image on new Pentax cameras.

On the point of pixel resolution, I have read that capturing an image on film is compared to 20 megapixels image, on a digital camera. so if an old lens was excellent for the film camera, why wouldn't it be good for the digital?

[westmill]

That's the question. Will the old lenses - produced for analog films with a limited resolution of 16 million pixels - still be good enough for the newest generations of camera's?

All lenses are different ! Its down to the individual lens here. The old 50mm f1.4 has been replace with the new 55mm f1.4
The older lens doesnt perform as good as the new one, when used wide open, but shut down a couple of stops there is not much difference.
But.... its not just about resolution..... the old 50mm suffers far more purple fringing etc.
Im sure some of the old lenses would still be very capable but there will be many that are not.
A lot depends on the design of the lens rather than the quality of the original build. Pentax do a really cheap 35mm f2.4 for example.
Its as cheap as chips.... but the design is perfect, and produces some of the best results available at any price at this focal lengh.
Its also worthy to mention the fact that the old lenses designed for 35mm have a bit of an auto uplift on the original use on 35mm
simply because when used on apsc you tend to get the sweet spot of centre lens performance.

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Last edited by westmill; 01-22-2012 at 04:50 PM. Reason: added info

[RioRico]

Worry not. Old lenses do not underperform on high-resolution sensors. Back in the day (like almost 40 years ago) I used some of the same lenses that now adorn my K20D, on both full-frame and half-frame (FF&HF) 35mm SLRs. (135/HF is about the same size frame as APS-C.) I often shot Panatomic-X or Kodalith or other EXTREMELY high-res films, with no optical problems. Resolution on such films *might* be matched digitally when APS-C sensors reach 100mpx. The lens is not the limiting factor. Worry not.

[myrdinn]

Worry not. Old lenses do not underperform on high-resolution sensors. Back in the day (like almost 40 years ago) I used some of the same lenses that now adorn my K20D, on both full-frame and half-frame (FF&HF) 35mm SLRs. (135/HF is about the same size frame as APS-C.) I often shot Panatomic-X or Kodalith or other EXTREMELY high-res films, with no optical problems. Resolution on such films *might* be matched digitally when APS-C sensors reach 100mpx. The lens is not the limiting factor. Worry not.

Fine. That's a relief. I can still be using my old lenses in the future, even with a x-millions pixels camera.

Thanks!

[falconeye]

Interesting question. But a proper answer would have to involve arguments based on MTF.

Such discussions run elsewhere. But let me say this much ...

1. Some (cheapo kit zoom) lenses are "outresolved" by low resolution sensors.

2. Some (regarded prime) lenses outresolve close to 1000 MP in the center, I tried with a special high resolution B&W film emulsion and was amazed when inspecting the film under a microscope ... no film scanner would be able to resolve this much ...

3. Better lenses equate to better images, and higher resolution equates to better images, whatever be the other factor. I.e., a sensor never is "too" high resolution for a lens.

[interested_observer]

Wonderful question that has come up every now and then. My opinion is that its not worth worrying about. Good glass is good glass, regardless of age, will continue to be good glass and will perform very well.

I will say that there are a couple of items that may contribute (but still not worrying about).

• Coatings - Digital glass has some additional coating on the rear element to cut down on reflections. Digital sensors are very shiny and thus highly reflective (take a look at it the next time you are blowing dust off of it). Older glass does not have these coating (since film is not that shiny), however I have never had any problems in this respect.
• Strike Angle - Digital sensors are optimized for light striking them that is perpendicular to the sensor's surface (90 degrees up and down). Digital glass tries to optimize the light rays path as they exit the glass to be as perpendicular as possible. Where this comes into play is with shifted and or tilted lens units. These are found on shift, tilt/shift lenses and on lens sitting on the other end of bellows that have a tilt/shift capability. What happens is that the center of the lens is shifted to one side of the sensor (for perspective control), and the light coming from it, strikes the sensor at a perpendicular angle. That is all well and good. However the light striking the rest of the sensor is not at a perpendicular angle, and you tend to see some fading, etc. On tilt lenses, the entire lens is tilted at an angle, which directs the light to the sensor at an angle that is anything but perpendicular to the sensor's surface. Film was not as sensitive as the digital sensor is with respect to strike angle of the light.

Again, its not worth worry about. I still like the M42, K, M, A, F and FA older glass. The older Contax glass lenses from Carl Zeiss are wonderful (and worth changing the mount on). There are a lot of older lenses out there, and in the Forum's lens reviews that are very worthwhile in acquiring when you find them. Usually, they are selling less than the newer glass (well they are not auto aperture or auto focus) - and well they are just old and for film camera anyway......

[TomB_tx]

Agreed that old lenses can be amazing. Ken Rockwell has a sample image (10 MB JPG) taken with a 1934 Leica Elmar 50mm f3.5 lens on a Leica M9. I sometimes use a 1941 example of the same lens, and I regularly use my lenses from 50s, 60s, 70s on my M9 as well. I have also had nice results from my Pentax-M lenses on my K-5, but with the K-5 finder my focus hit-rate is much lower than with the M9 (or an old fim Pentax). When I hit focus with the Pentax-M the images compare well to my new Pentax lenses.
It's not that the new lenses aren't good, but the good examples of older lenses are better than people expect.

[Barnster]

Back in the 60's,70's and even 80's,'megapixels' wouldn't of even been in vocabulary when they built these lenses like the K and M series.They would have been built for quality and giving Pentaxians the best optics possible on all levels of affordability.That's why these types of lenses have stood the test of time.I don't think it will matter how many megapixals a Pentax DSLR is or will be.These older lenses will still shine into the future and give us all great results.

[Canada_Rockies]

I regularly use two M lenses. As I am only using a K10, I am sensor restricted to resolution of 10 Mp. However, I used a 55 mm f/2.2 preset lens built in 1957 on my 1957 Pentax to take images on 10 and 25 ASA Kodachrome. The lens was still better than the film resolution, and it was HUGE. More recently I used Ilford chromagenic black and white film in a film KX using K 55/1.8, M 28/3.5 and M 135/3.5. The lens resolution was greater than the film. Someone mentioned 100 Mp above, and that might be underestimated.

The major problems I have with the two M lenses I own are with me, not the camera, not the lenses. My last upload to the forum was a little bird taken with the M 400/5.6 at 45 feet away, and it is soft. Close examination shows that I focused a bit in front of the bird - the wing feathers are much crisper than the head. I did not have time to rig with the tripod. The lens did not fail, nor did the camera, only the nut holding it.

[TomB_tx]

I regularly use two M lenses. As I am only using a K10, I am sensor restricted to resolution of 10 Mp. However, I used a 55 mm f/2.2 preset lens built in 1957 on my 1957 Pentax to take images on 10 and 25 ASA Kodachrome. The lens was still better than the film resolution, and it was HUGE. More recently I used Ilford chromagenic black and white film in a film KX using K 55/1.8, M 28/3.5 and M 135/3.5. The lens resolution was greater than the film. Someone mentioned 100 Mp above, and that might be underestimated.

The major problems I have with the two M lenses I own are with me, not the camera, not the lenses. My last upload to the forum was a little bird taken with the M 400/5.6 at 45 feet away, and it is soft. Close examination shows that I focused a bit in front of the bird - the wing feathers are much crisper than the head. I did not have time to rig with the tripod. The lens did not fail, nor did the camera, only the nut holding it.

I agree! Erwin Puts showed a comparison on his website of the same lens and scene on a Leica M9 (18MP FF) and film Leica film camera, I believe using the Ilford film. With extreme magnification it was clear that the film showed better fine detail than the 18MP sensor of the M9. That said, the M9 is capable of great images.
I also remember an article "back when" showing how Kodak printed huge murals (Grand Central Station?) of something like 18x28 feet from 35 mm Kodachrome. (After all, the 24x36 frame was twice what most movie theaters used at the time.)
People today undersestimate what film could do. Perhaps it's the scanning from film to digital that is the weak link.