Jump to content

Lenses should have megapixel ratings


Andrew Reid

Recommended Posts

Sorry Andrew, but you have no idea what you're talking about in this case. Most of those kit lenses resolve far more than 6mp.

Why hasn't someone made a megapixel chart for lenses? That would give the manufacturers the shits no doubt!!

​I print my own resolution charts, even one based on various contrasts, they're always in line pairs, which you translate to line pairs per millimeter on the sensor or film, which you can translate into minimum megapixels to respresent this frequency if you so wish.

EG; this is a downsized crop from the type of charts I use sometimes, I've got various. The height between the arrows on the chart is approx 3.3mm on the film negative, element 8 is resolved, which is 800 lines over 3.3mm which translates to 121 lp/mm(or 242 pixels/mm minimum) which is about the maximum this scanner will resolve off film, which translates to 50.6mp minimum. On a microscope it's over 150 lp/mm (over 80mp), this is just a Canon FD 28mm @ f/5.6 or f/8. I use this for digital cameras too.

 

If we're talking about 6mp on APS-C, that's going to be around about 60 lp/mm iirc, I've never had any lens test that low that I've tried, and kit lenses are not the worst lenses I've tested, some older lenses I've tried are worse than any modern kit lens I've used.

9jOXyGy.jpg

Link to post
Share on other sites

This would be near useless for me and most folks I work with. Any modern production lens will resolve enough detail to keep you from getting a pink slip. I wouldn't project some lenses 40' tall but for youtube or even broadcast I would rank a lens' resolution numbers near the lowest of important characteristics for my uses as a cinematographer. The overall aesthetic performance of a lens is what matters, followed closely by ergonomics. The former is not something a lens review will tell you much about. You might be able to spot some bokeh and vignetting characteristics, but short of renting it and pointing it at a person and looking at them in a few sizes you won't know much about a lens. The only reviewer I see doing any work like this is Lloyd Chambers of Diglloyd.com: his in-depth reviews, aperture series, and expert commentary are worth every penny of his subscription costs.

When the Sigma art 35mm 1.4 came out I rented it for a comparison to my beloved Zeiss ZE 35mm 1.4, and yes the Sigma could have an edge in resolution in some scenarios, but the Zeiss trounced it in terms of pure image harmony. Switching blind A/B on the monitor my crew all settled on the Zeiss. Just goes to show you DxO mark resolution numbers should not be a huge consideration in your purchases unless you are in the business of photographing and making reproductions of test charts.

Link to post
Share on other sites

the resolving power of a lens condensed down into a simple number is a great idea.  industrial cameras are sold in this way, why not high end lenses.  

MTF charts are tough to interpret for beginners.

Not sure if one number alone would tell enough about a lens though.

One simple way of presenting it would be to split it up into three numbers: center point resolution (best case), edge resolution (worst case), and then an average resolution based on a number of samples taken from edge to center of the lens. This could tell quite a bit without having it presented only in a MTF chart.

Link to post
Share on other sites

Lenses don't resolve in Megapixels and giving them a Megapixels rating would be misleading.  So your saying that a kit zoom on a 24MP camera would give you the same result as a top end prime on a 6MP camera.  I think you will find it doesn't which is why you can't rate lenses in Megapixels. 

 

completely agree on the t stop rating though.  It ridiculous that you can buy a an f2.8 lens but only to really get f3.5 or whatever.  False advertising really. 

Link to post
Share on other sites

There is a reason why, when Nikon introduced the D800, they listed a set of lenses that were up to par for the 36mp resolution of that camera. I have a few less expensive lenses like to 70-300 which look great using my D700, but on the D800 it does not come close to the resolution of my 70-200/2.8 and I can see the difference easily. I'm a pixel peeper though to some extent. For video, especially only HD rather than 4K, is it as noticeable as with stills?

Link to post
Share on other sites

This would be near useless for me and most folks I work with. Any modern production lens will resolve enough detail to keep you from getting a pink slip. I wouldn't project some lenses 40' tall but for youtube or even broadcast I would rank a lens' resolution numbers near the lowest of important characteristics for my uses as a cinematographer. The overall aesthetic performance of a lens is what matters, followed closely by ergonomics. The former is not something a lens review will tell you much about. You might be able to spot some bokeh and vignetting characteristics, but short of renting it and pointing it at a person and looking at them in a few sizes you won't know much about a lens. The only reviewer I see doing any work like this is Lloyd Chambers of Diglloyd.com: his in-depth reviews, aperture series, and expert commentary are worth every penny of his subscription costs.

When the Sigma art 35mm 1.4 came out I rented it for a comparison to my beloved Zeiss ZE 35mm 1.4, and yes the Sigma could have an edge in resolution in some scenarios, but the Zeiss trounced it in terms of pure image harmony. Switching blind A/B on the monitor my crew all settled on the Zeiss. Just goes to show you DxO mark resolution numbers should not be a huge consideration in your purchases unless you are in the business of photographing and making reproductions of test charts.

​I could not agree more!  It is the "feel" of the lens that really counts, not a bunch of (sometimes) questionable testing.  Shoot the lens.  If it feels good and you like the results, it is a keeper!

I shoot with a range of lenses.  Sometimes everything comes together and I get a few great shots, sometimes not.  But if I look at the lenses that have captured the spirit of a shot, it is quite often not the best, highest resolution, more expensive lens in the bag...

Link to post
Share on other sites

so i,m confused will my canon 50mm FD which shoots amazing images on film and has done for many years not be any good on 24MP digital camera i can,t quite fathom what this is about if the lens shots well on film surely it going to look great on digital i mean what is the resolution of film i did a quick google and and ken rockwell thinks you would need 175MP camera to resolve the detail of 35mm film 

 

so can some one explain this a bit further for me

 

 

Link to post
Share on other sites

If you showed an average consumer a picture taken with a $100 kit lens, next to the same picture taken on the same body at the same focal length with a $1200 lens - they may or may not see much difference.

I did a lens comparison a while back between Leica R, Zeiss ZE Primes, Canon L series primes, and 60's/70's era Nikkor primes and there was no difference to my eye between any of them except for a slightly wider dynamic range with Leica. All other optical aspects like sharpness and color were visually identical. That's a pretty wide range in years and lens cost and I would suggest that even the top cinema prime is no more than maybe 5% better optically than any of these I tested.

Link to post
Share on other sites

so i,m confused will my canon 50mm FD which shoots amazing images on film and has done for many years not be any good on 24MP digital camera i can,t quite fathom what this is about if the lens shots well on film surely it going to look great on digital i mean what is the resolution of film i did a quick google and and ken rockwell thinks you would need 175MP camera to resolve the detail of 35mm film 

 

so can some one explain this a bit further for me

 

 

He's insane. But that lens should be sharp on anything by 50mm.

A modern lens will have better contrast. If it looks great on film it won't look worse on digital.

Link to post
Share on other sites

He's insane. But that lens should be sharp on anything by 50mm.

A modern lens will have better contrast. If it looks great on film it won't look worse on digital.

 

​By f5.6.

 

Fwiw, to whomever above said the Leica lens has better DR.... that just means worse contrast. :(

 

The whole "vintage" thing was set off largely because worse lenses provided a better "look" on digital cameras.

Link to post
Share on other sites

so i,m confused will my canon 50mm FD which shoots amazing images on film and has done for many years not be any good on 24MP digital camera i can,t quite fathom what this is about if the lens shots well on film surely it going to look great on digital i mean what is the resolution of film i did a quick google and and ken rockwell thinks you would need 175MP camera to resolve the detail of 35mm film 

 

so can some one explain this a bit further for me

 

 

Generally speaking he's pretty wrong, that's even above the 1000:1 contrast figure Kodak gives for T-Max 100.

Regular commonly available film peak resolution can range anywhere from an equivalent of 6mp to a bit over 80mp in 35mm format in lower contrasts, Henning Serger's test can get that upper figure out of many slide films and B&W, I get a bit less than him on most films, my lenses aren't as good as his, but I use wide angle lenses in my tests. Less common films can score way way past 175mp, reproducing this detail off the film is a major issue though. There's a few issues that may cause a good film lens to be poor on some digital cameras, but most of mine work really well on most digital cameras I've put on them.

 

Film users shooting for detail will typically user bigger than 35mm formats though.

Link to post
Share on other sites

so ok bit of research and found this see link  , so no i don,t think we need to worry about our films lens for quite some time on digital sensors 

and the chairmain of cooke optics calls the whole 4k lens thing a red herring ...i think my old glass is fine 

 

http://www.cookeoptics.co.uk/techdoc/AFEEAD0010089A9585257BB40064E20F/Are your lenses good enough for that 4k high definition camera.pdf

Link to post
Share on other sites

so ok bit of research and found this see link  , so no i don,t think we need to worry about our films lens for quite some time on digital sensors 

and the chairmain of cooke optics calls the whole 4k lens thing a red herring ...i think my old glass is fine 

 

http://www.cookeoptics.co.uk/techdoc/AFEEAD0010089A9585257BB40064E20F/Are your lenses good enough for that 4k high definition camera.pdf

​yes I love when we find a simple and elegant white paper that uses science to solve our fears and rises above marketing.

Link to post
Share on other sites

In performing tests with older glass, don't forget about sensor stack height.   The lenses themselves  might be able to resolve x amount of detail, but mated to a camera its not designed for can produce less optimal results. 

Link to post
Share on other sites

"The same clarity needs to be applied to aperture (f-stop) in relation to brightness (t-stop). The Canon 24-70mm F2.8L I (original version) and EF-S 17-55mm F2.8 for instance DXOMark rates at T3.6! The difference is highly noticeable in the real world with my Tamron 24-70mm F2.8 VC a T3.0 and far brighter than my Canon wide open. Showing the T-stop of the lens on the box next to F-stop would help allow the consumer to make a more informed choice especially if they need to shoot in low light."

Everyone's getting pretty worked about the megapixel thing, but the T-stop idea is great. For instance, I've been testing the Sigma 18-35, and it's no where near 1.8. Probably more like T2.5.

Link to post
Share on other sites
  • 4 weeks later...

 There is no correlation between lens sharpnes and Mpx. Mpx say how many "things" records light. Lens sharpnes mean how good optic focus light in the point, Which is imposible to do exactly. Before the sensor u have micropoptics too. Always u can use Sigma sharper but noisier Vaveon sensor n that sensor dots use "math tricks" to create pixels that dont exist to whole create image.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...