There is a difference between sharpness and resolution in a digital image.

I see too many Internet photo forum conversations by wannabe experts that confuse people on this issue. So my mission today is to get a bit more technical than usual and explain that sharpness and resolution are in no way related.

Now if I get too technical, don’t worry about it. Just ignore the basis of my argument and accept the concept that you can have a 14 megapixel sensor that doesn’t produce images that are as SHARP as a camera with a six megapixel sensor. In other words, sharpness and resolution have ABSOLUTELY NOTHING TO DO WITH EACH OTHER!

Here’s why. Resolution is not the number you see from the camera manufacturer. It doesn’t matter if you have an eight megapixel camera or an 11 megapixel camera. The true mark of your particular camera’s resolution is how many horizontal line pairs it can resolve given a certain lens mounted to the body. Resolving power comes from measuring the PICTURE pixels on your camera (not the same as the total number of pixels) for their ability to resolve data line pairs – per image height (and width). I know I may have lost you there. Your mind turned to mush. It’s based on linear algebra folks and it sucks. But trust me, it’s accurate.

There are additional measures of camera resolution; picture pixels and recorded pixels. Again – these measurements may have nothing to do with the total size of your camera’s sensor.

The second part of today’s post has to do with sharpness. This will really blow your mind. You can have a brand new Nikon D3 ($5000) with its massive sensor, and it may not be as SHARP as a Canon 40D with a smaller sensor. Why?

Because there are several variables that impact sharpness and have NOTHING to do with resolution. If you put a cheap, consumer lens on the Nikon and an expensive, pro lens on the Canon, it may outperform the Nikon.  (By the way – the reverse is true. I could have come up with an example switching Nikon and Canon around. It doesn’t matter which brand you use.) Likewise, things like image processing, anti-aliasing filters and a host of other technologies that get in between the image and the sensor will cause differing degrees of sharpness.

So I hope you see the lesson here. The “My megapixels are better than your megapixels” discussions I see floating around on the photo boards are utterly stupid.

Don’t think you need that next 200 megapixel camera to get a sharp picture. You do not.

NOTE: I can’t devote enough time or space to turn this into a white paper, so invariably, someone will chime in with “You forgot to mention…” Please recognize I didn’t necessarily forget anything – I just may have decided not to include every technical detail for clarity or brevity’s sake.
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This post sponsored by the Digital SLR Store

Join the conversation! 30 Comments

  1. Thanks for a very insightful and well-put post. Just wanted you to know that my several years old 6 Mpx camera with the right lens, still gives me a great deal of satisfaction after inching up from rank-amateur to somewhat more skilled amateur. And I still love many of my photos when printed at 13×19 and greater. Composition, the right glass, “look up, look down, look all around” and a good tripod have served me just as well as dropping another 1k on 5 more Mpx.

    Also…Love the podcast! Keep up the awesome work!

    Reply
  2. To add to that, it’s also important to consider ISO and de-noising. Using the 40D and D3 example, at high ISO the 40D is going to need more de-noising then the D3 because of it’s smaller pixels. De-noising generally leads to some loss of sharpness.

    Reply
  3. With regards to the final result I find that different folks like different strokes! In other words I find that some people prefer photo’s that are sharper than others. The subject matter will also affect this choice. I took what I thought was a pretty good self portrait a while ago, but excessive sharpening highlighted every defect on my face! Backing it off made me look a lot more attractive!

    Also, if you wear eye glasses, get your eyes checked regularly! Your photo’s will appear much sharper if your eye glasses are the correct prescription for you eyes!

    Reply
  4. Tony while you comment is accurate – it’s not terribly on point. We’re not talking about the final result. We’re talking about understanding the difference between resolution and sharpness.

    Reply
  5. True Scott. I guess I got on my soapbox. Apologies for the distraction. Perhaps it would make for a good future discussion? How to tell when you have the right level of sharpness? It’s actually more difficult than I thought.

    Reply
  6. But if SOME is good, MORE is better. Simple math. FWIW I have modified my 40D so that it goes to 11. That’s 1 louder isn’t it?

    It drives me crazy to hear the salespeople at the big box upselling the suckers by quoting the higher megapixel count.

    Is my math bad or is HDTV 1080P approx 2MP? 1080P sounds better.

    Reply
  7. Thanks, Scott, for a reassuring post.

    I’m only a couple of years in as an avid hobbyist and aspiring professional photographer and I’ll admit I was initially frustrated at the sharpness (or lack thereof) the camera was producing. Sure enough, when I replaced the kit lens with some nice glass, it’s like night and day!

    My question is this: Is there a searchable database that contains statistics / analysis of the cameras in such a way as to determine whether Camera A is “sharper” than Camera B given equal configurations (lens, lighting conditions, etc.) or are we still best off consulting any of the various in-depth reviews available on the internet?

    There are some fantastic detail-oriented reviewers out there! I’m just curious after having read this article if there is such a place out there.

    Reply
  8. Thanks for your website. Please continue your efforts. As a suggestion on this article, your argument might have been made easier and clear if you included comments on what does increase sharpness (as Jamie started to address).

    Reply
  9. Ron I see your point but am not sure I agree with it. The point of this post – as I intended it – was to help people see that sharpness and resolution are not tied together – not how to get pictures. That said – I did give the basic info – that the best glass usually leads to the sharpest image and accordingly, sharper at three megapixels, six megapixels, 12 megapixels, etc.

    Reply
  10. I am new to your site and was drawn to the title – always looking tips on better picture quality, particularly sharp, crisp pictures. I guess you were really talking to those who think that the more megapixels, the sharper picture. The short answer to that is the more megapixels the more “potential” for sharper pictures, particularly as you are going for larger images. Larger mega pixcels maintians picture quality as you increase the size of the image. However the quality/sharpness of the images is more a function of controling light and therefore know how to use the camera features and addons.

    So (for given camera) the photographer should focus on quality of your lense and how to use the camera features. Or in choosing a camera, focus on the camera specs eg sensor, etc. And for the size images that most people want they probably don’t need mcuh more that 6 megs (I’m told – not a techy myself but understand the point). So the real message is to not focus on resolution but on tips and tricks to understanding how the camera features work and photo techniques.

    Reply
  11. Great post Scott. If I may, can I ask a follow up question?

    Does the size of the medium have anything to do with the resolution of the sensor? I have heard that Medium Format digital have a high resolution then their APC-S and Full Frame brethren. If this true? Is that because there is just more real estate for they have more room for picture pixels?

    Reply
  12. Hi Scott. I love Linear Algebra. Indeed, I teach do Linear Algebra. I’d actually love a chance to delve into it. However, I understand your point completely. I guess the mega-pixel chasers need to justify their purchases somehow. I have no problem understanding how the quality of glass impacts how faithfully fine details are recorded in an image.

    Reply
  13. I think I see your point, but it is not entirely clear. I must’ve got lost on the way.

    Reply
  14. David that is a great question and if you read my post the answer is there – it’s not that it’s a larger sensor on the digital medium format backs – it’s that they have bigger PICTURE pixels NOT the recorded pixels or pixel count. It’s a fine point but an important one. Yes the medium format backs have the potential for higher resolution because they have better picture pixels but AGAIN – this isn’t a function of sharpness.

    And Ron – it seems I can’t disabuse you of the notion that megapixel count (resolution) is tied to sharpness. You’re wrong but certainly entitled to that opinion. But I am going to make it clear to the rest of the audience that I think you’re wrong – and they can decide who they want to believe.

    You’re not helping anyone by promoting that viewpoint.

    Reply
  15. Hi Scott, i was wondering what is the standard resolution that camera’s output? i have a canon 30d and mark2n and when i download the images are usually at 240dpi. is this the default? i know that resolutions should be set on what you are outputting to, web, video, print, etc….. is there anything that you would recommend to get better sharper images on output in terms of dpi?

    thanks for starting the site, i listen to the podcast all the time.

    aloha brady

    Reply
  16. Hi Scott, i was wondering what is the standard resolution that camera’s output? i have a canon 30d and mark2n and when i download the images are usually at 240dpi. is this the default? i know that resolutions should be set on what you are outputting to, web, video, print, etc….. is there anything that you would recommend to get better sharper images on output in terms of dpi?

    thanks for starting the site, i listen to the podcast all the time.

    aloha brady

    Reply
  17. Scott,

    My point was quite the opposite. I was agreeing with you that megapixels has nothing to do with picture sharpness (with the caveat that megapixels help you maintain picture quality if you need to blow up image sizes – which I probably said badly). I was trying to suggest that you would have made your point easier and clearer if you spent more of your comments pointing megapixel enthusiasts what does effect sharpness (which is a function of other camera feature and techniques). I am fairly new to blogs and see it is harder make your point than it seems.

    Reply
  18. Why is the Nifty Fiddy aka the Canon f/1.8, 50mm so sharp, that’s a cheap lens???

    Reply
  19. Scott,

    Is it possible to under play this mega pixel issue as well? I have a Canon XSi, and my best lens is my 70-200 f4 L, in good light I can milk every one of those mega pixels out of my set up. My friend has a Nikon D70 that is 6mp, and there is dramatically less information in his photos. I agree with your point that people will be after the highest mp camera, then use it with a crappy kit lens, never realizing the frames potential. I just wounder if the mp craze has at least some validity in improving exposures. In my searching I found that a rough estimate of a color 35mm film at 100 ISO is 8-12mp, and 20mp B&W. This means that only recently has digital achieved films potential it terms of resolution. In the light of the fact that pushing the mp seems like a a reasonable endeavor. I would like to see less noisy ISO, but it seems digitals are pretty far ahead of film in that department already, although I do find myself wanting for better ISO more often then more mp.

    I guess my point is simply this, I realize that mp seems to be the most over played part of the exposure equation, but it seems like some pros are so eager to dispel the mp central importance that it comes across that the mp are of little or no value. I am simply making the point that mp are part of the equation (one of many) , and depending on the application a critical one.

    Reply
  20. Scott,

    Is it possible to under play this mega pixel issue as well? I have a Canon XSi, and my best lens is my 70-200 f4 L, in good light I can milk every one of those mega pixels out of my set up. My friend has a Nikon D70 that is 6mp, and there is dramatically less information in his photos. I agree with your point that people will be after the highest mp camera, then use it with a crappy kit lens, never realizing the frames potential. I just wounder if the mp craze has at least some validity in improving exposures. In my searching I found that a rough estimate of a color 35mm film at 100 ISO is 8-12mp, and 20mp B&W. This means that only recently has digital achieved films potential it terms of resolution. In the light of the fact that pushing the mp seems like a a reasonable endeavor. I would like to see less noisy ISO, but it seems digitals are pretty far ahead of film in that department already, although I do find myself wanting for better ISO more often then more mp.

    I guess my point is simply this, I realize that mp seems to be the most over played part of the exposure equation, but it seems like some pros are so eager to dispel the mp central importance that it comes across that the mp are of little or no value. I am simply making the point that mp are part of the equation (one of many) , and depending on the application a critical one.

    Reply
  21. Gary if most of the people talking about megapixels knew the difference between picture pixels and recording pixels – none of this hoopla would be an issue – but frankly – unless you’re making very large prints – no DSLR on the market today has a significant advantage here if all you’re looking at is the number of megapixels. There are situations where the MP matter – but changes are, almost all of the time they don’t. I have hundreds of images published in books and magazines that were made with my first DSLR – the Canon D30. All 3.3 megapixels did their job and created great images.

    Reply
  22. Gary if most of the people talking about megapixels knew the difference between picture pixels and recording pixels – none of this hoopla would be an issue – but frankly – unless you’re making very large prints – no DSLR on the market today has a significant advantage here if all you’re looking at is the number of megapixels. There are situations where the MP matter – but changes are, almost all of the time they don’t. I have hundreds of images published in books and magazines that were made with my first DSLR – the Canon D30. All 3.3 megapixels did their job and created great images.

    Reply
  23. @thehalfshow.com – I would imagine (besides being a Canon product) that it’s because it has so few internal elements to soften the result.

    @Gary – The Xsi is out? I’m only seeing pre-orders…

    Reply
  24. @thehalfshow.com – I would imagine (besides being a Canon product) that it’s because it has so few internal elements to soften the result.

    @Gary – The Xsi is out? I’m only seeing pre-orders…

    Reply
  25. Mark,

    Of all places I got it at walmart, I was waiting for B&H to have it, but I couldn’t resist when I saw it at the same price as B&H at walmart.

    Reply
  26. Mark,

    Of all places I got it at walmart, I was waiting for B&H to have it, but I couldn’t resist when I saw it at the same price as B&H at walmart.

    Reply
  27. Thanks Mark I didn’t think of that! I just broke my 50mm the other day, I was wondering why I loved her so much. Thanks again and I enjoy “Golden Spring” too!

    Reply
  28. Thanks Mark I didn’t think of that! I just broke my 50mm the other day, I was wondering why I loved her so much. Thanks again and I enjoy “Golden Spring” too!

    Reply
  29. Agreed with scottbourne.

    Quote: “My megapixels are better than your megapixels” is just like saying: “my mph is better than your mph”, it doesn’t make sense, as megapixel is considered a term for measurement.

    Likewise, it’s quite often you hear people comparing a Farrari to a Nissan GTR…..”the Farrari has got more horespower than the GTR….”, similar to ” a Leica better than a Canon..”. Both are high-performance sportscars, and at the end of the day, the GTR beat the Ferrari because the driver understands the car performance and the road condition better.

    Reply
  30. Thanks for these information.. but I’m still a little confused about resolution and sharpness..
    if only you could share some images about this topic it could be more comprehensive ..
    thanks ;)

    Reply

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About scottbourne

Founder of Photofocus.com. Retired traveling and unhooking from the Internet.

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