Jump to content
Andrew Reid

Lenses should have megapixel ratings

Recommended Posts

EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

There must be a way to express something more comprehensible to the less involved that isn't so highly accurate, but still does the trick, don't you think?

Would really make sense nowadays, I believe. With the exploding megapixel counts of sensors and everything.

Share this post


Link to post
Share on other sites

There must be a way to express something more comprehensible to the less involved that isn't so highly accurate, but still does the trick, don't you think?

Would really make sense nowadays, I believe. With the exploding megapixel counts of sensors and everything.

Nikon has golden rings, canon has L letters, sigma has the art series...

I would prefer instead for the average user to use their brain a bit better than have a company find better ways to "advertise" their products.

Share this post


Link to post
Share on other sites

There must be a way to express something more comprehensible to the less involved that isn't so highly accurate, but still does the trick, don't you think?

Would really make sense nowadays, I believe. With the exploding megapixel counts of sensors and everything.

​MTF charts published by lens producers are already greatly reduced in complexity, in that in general they only show contrast for two spatial frequencies (usually 10 and 40 lp/mm) and two aperture values (usually wide open and f/8) and two image plane orientations (sagital and tangential). The "full" MTF is a four dimensional quantity which is difficult to represent in 2 dimensions. I put "full" in quotes because it also depends on focal length for a zoom lens, and, to an extent, on the focus distance thus it can be a six-dimensional object.

I hope you can appreciate why it's impossible to boil a six-dimensional function down to a single number. You could simplify it further and measure the MTF at a few distances from the image centre (centre, top/bottom edge, left/right edge and extreme corner), but it's been heavily simplified already and that would cut a lot out.

You could try averaging the figures but the range you average over would be fairly arbitrary and subject to differences between manufacturers. And the idea that manufacturers attach a resolution figure to the lens in order to sell them would just open the flood gates to clever ways to inflate the score by carefully choosing what to include/exclude.

Share this post


Link to post
Share on other sites

I'm sorry to say, but i think it's a terrible idea. We know how the consumer operates, people would then only look at the this megapixel count, as they already do with cameras. It's already not a good thing with cameras but it can make sense i guess sometimes, because it can be important. A lens is sooooo much more than its  megapixel resolving power. Besides, most people actually don't care enough to really mind if it has a high resolving power or not. Like you said, a lot use the kit lens and they're very happy with it, it's good enough for them and the may not want to spend any more money on it. The few others who know enough about lenses, optic, and photography in general to really be interested in this matter, also know enough to go look for reviews, test, advice, photos on flickr etc...
Plus, people would always ask "how many megapixels does that lens resolve" without know anything else about the lens, only focalizing on this, when everything else about a lens is so interesting and important. And to conclude, i guess MTF charts are there solely for that purpose.

Share this post


Link to post
Share on other sites

Could not disagree more. It would be the second coming of the Megapixel race in pocket cameras for dumb consumers.

I give you an example as to why. Say you have a lens thats listed it as 40 mp on it. Yea it may resolve that, but hows the image? Bokeh? Chromatic Aberration? When sharpness becomes the main concern for manufacturers (more than it is now) then we all suffer creatively for it. 

As someone that uses Cinema glass on his GH4 you know that resolution is not the most important aspect of an image :)

Share this post


Link to post
Share on other sites

in a canon 5ds event a while ago they admitted that most of the canon lens lineup will not be suitable for their new 50 megapixel flagship, and they showed an internal list that only the newer (higher priced) top lenses do really do the resolution justice.  they also know that the newer zeiss and sigma primes are great and will work.  nevertheless serious MP count for lenses and stickers might be problematic, as there are still too many factors involved in image results.

what indeed is very important for filmers who are limited in light and through high iso noise is the transmission, which also indeed is very different on lenses in unexpected ways.  looking at these values is definitely important before buying and more important than the official f-stop-value alone.

Share this post


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.  

 

If a manufacturer is going to sell a camera based on its sensor resolution they should also provide lenses capable of delivering this.  Ie.  Canon will use thier 50+ mpx count of the new 5d as a selling point.  they won;t show the camera fitted with an otus or a schneider/rodenstock digitar + helical.  they'll show it with a Canon L lens, which most are incapable of delivering resolutions that actually warrant the huge file sizes and the premium price Canon will command for the high mega pixel count.  

People use medium format backs of 80mpx for a reason - there are lenses that deliver this resolution onto 56x56mm.  there are few 135mm format lenses that will be marketed alongside the 5dmk4 (50mpx), but the canon consumer will be told their lenses designed and capable for 35mm film will still meet the demands of pixels sizes smaller than 100iso film grain.

Everyone knows that there is more to a lens than resolution.  but if a consumer is buying a camera sold with its megapixel count used as a selling point then they should be made aware of their options.  It's like selling a Ferrari based on its ability to go 300mph using a new type of fuel, a fuel not yet developed.

 

 

 

Share this post


Link to post
Share on other sites

Not sure if the megapixel label on the lens is necessary, but 100% agree on the T-Stop. I used to wonder why the Samyang cine versions are slightly darker, but they have the accurate T-Stop instead of F-Stop listed, of course the cine versions let in the same light as the standard versions. T-Stop for videography is absolutely crucial. I'd be furious if i had bought the Canon F2.8 L for video work and later found out that the T-Stop is actually close to 4!!! Wonder how my Zuiko OM 35-80 F2.8 compares.

 

Share this post


Link to post
Share on other sites

​But for 4k Video, one only needs 8megpixels, right?  So I guess sony might or might not depending how important video is for them.

​As stated before, lenses already have mtf charts, which are fairly easy to read, at least for the enthusiast, and MUCH more useful. Most "4k" lenses aren't hitting close to 100% mtf at APS-C 4k, at least wide open, so to some extent a bad lens is a bad lens even at 8MP. 

In sum, megapixel ratings for sensors are stupid and tell only a portion of the story. "Container" ratings (1080p/4k/etc.) are even more meaningless... clearly the 5D isn't hitting 100% of 1080p's available spatial resolution. Film stocks had mtf curves, much more useful. "Lens megapixel" ratings are somewhere in-between megapixel ratings and "container" ratings, as regards stupid.

Shoot and test and read charts.

Share this post


Link to post
Share on other sites

I'm going to go ahead and say that the average consumer actually doesn't really care. They buy based on numbers because in their mind higher megapixel = better. They have no understanding of why, or how - but that's the thought process.

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.

But they're unlikely to go out and spend an extra $1100 on a lens. Most consumers are baffled when you tell them a single lens can cost $100,000. 

Professionals buy expensive lenses because they appreciate and understand the very reason they're expensive. Professionals (and even enthusiasts, I guess) care about the quality of all the components, because they know the difference it makes to the picture.

Consumers don't get it. Realistically, someone who's just picked up a camera is unlikely to take amazing photos even if they have a $1200 lens on it.  

Share this post


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...