Tag Archives: Technique

Equipment, Technique

Some Thoughts on Aperture and DOF and Related Issues

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(This post is slightly adapted from something I recently posted in a photography forum in which hyperfocal distance, “DOF calculation” software, and related issues were under discussion.)

Shooting as a way to learn to understand how things like depth of field or “hyperfocal distance” work is a great idea – it is perhaps the best way to understand these concepts. I firmly believe that it is better than relying on tools such as software DOF (“depth of field”) calculators or tables. Fortunately, it is easy to do some basic experiments related to aperture and DOF and the so-called hyperfocal distance.

(The term hyperfocal distance can be interpreted in a couple of ways. In photography, this is often thought of as the distance at which you might focus in order to place objects at different distances in focus. If there is an object that is 15 feet from the camera and there are important subjects at infinity, the hyperfocal distance lies beyond the object that is 15 feet away and closer than the far away objects that might be in focus with the lens set to “infinity.”)

To find out about the effect of aperture on DOF, try the following:

  1. Put the camera on a tripod and compose some reasonable test image that includes subjects at various distances from the camera position, with a primary subject somewhere between the closest and the furthest.
  2. Focus on your primary subject within the scene.
  3. Shoot a series of images at apertures ranging from the largest to perhaps f/16 – shoot at f/1.4, f/2, f/2.8, etc. You might want to go as far as f/22 on full frame.*
  4. If you want to be a bit more methodical, you can use your DOF tables/software to “calculate” your hyperfocal distance, focus there, and repeat the process – but, frankly, I wouldn’t bother.
  5. Spend some time – likely well under an hour – looking over the results on your computer. If possible, make a few small prints to confirm the relevance (or not) of what you observe on the screen.

Another great way to understand the effect of aperture on the depth of field in your shot is to shoot in live view mode on your DSLR. Here you can press the DOF preview button, zoom in the live view display to 5x or 10x magnification, and pan around the magnified image on the rear display to see a very good approximation of the effect of your aperture choice on elements of the scene at various distances from the camera.

SIMPLIFICATION: A SECRET

Let me share a little secret. From reading some photography forum posts, you might get the idea that lots of photographers are going around making careful and technical calculations of precise hyperfocal distance and DOF and all the rest and then making exactingly accurate choices about aperture for each shot. In general, it doesn’t work that way in the real world, where photographers often tend to select aperture in basically three ways:

  1. In a shot where the subject doesn’t have a lot of depth and DOF isn’t really an issue, we tend to shoot at some default aperture that we believe is more or less optimal for overall resolution, corner resolution, and perhaps vignetting. On full frame, this might frequently be roughly f/8, though there are reasons to vary from that a bit sometimes.
  2. When working a subject on which we want very large DOF, we tend to go straight to the smallest aperture that we feel will produce large DOF and very good resolution. For me, this is typically f/16 on full frame, it might be no smaller than f/11 on cropped sensor cameras. There are situations in which I might use a smaller aperture, but they are very rare and will involve acceptance of some tradeoffs.
  3. When faced with a shot in which we want very narrow DOF, we tend to open up as much as we think we can, perhaps tending toward the largest aperture on the lens we are using. There are some additional factors to consider here, but I’ll leave them out for now in the spirit of simplifying.

So, a simple generalized approach:

  • Shoot at some middle-of-the-road aperture when DOF isn’t a major concern.
  • Shoot at the smallest acceptable aperture when you want large DOF – f/16 on full-frame or f/8-f/11 on crop.
  • Open way up when you want to minimize DOF.

This approach works in a wide range of real-world photographic situations, and it is especially useful to begin with it when you have to work quickly. There will be situations in which these are simply starting points, and you’ll need to make some modifications – for example, in very low light you might not be able to use that very small aperture if you are shooting hand-held, or your largest aperture might produce DOF that is too narrow for some subjects, and so on. But starting with this simple basic concept, using live view DOF preview when appropriate, and learning from experience will likely move you a lot further along on the road towards understanding and making effective use of aperture/DOF than trying to rely on some DOF calculator. (Depite their appearance of accuracy, these calculators depend on a bunch of assumptions that may not match up with your photography.)

* You can stop down further on cameras with larger sensors before you run into issues with diffraction blur, a softening of the overall image that occurs with the smallest apertures. To generalize, while you can stop down to roughly f/16 on a full frame and still produce very sharp images, you might want to avoid such a small aperture on your cropped sensor DSLR, perhaps avoiding anything smaller than about f/11… and you might want to be a bit cautious about using f/11.

© Copyright 2012 G Dan Mitchell – all rights reserved.

G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
Blog | About | Flickr | Twitter | Facebook | Google+ | 500px.com | LinkedIn | Email

Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.

Commentary, Equipment, Technique

Thoughts About the Canon EF 100-400mm f/4.5-5.6L IS Lens

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(This is another post based on something I wrote elsewhere as a response to a question about this lens – I’m re-sharing it here with minor editing.)

I’ve used the Canon 100-400mm f/4.5-5.6L IS lens  a lot – for things as varied as handheld shooting of bicycle races and tripod-based landscape photography. Over time I’ve developed a few thoughts about the performance of this lens and some of the comments that I frequently hear and read about it.

First, especially from my tripod-based work, I have found that the lens is capable of very good performance in terms of image quality – e.g. “resolution.” This is true at all focal lengths, but more so perhaps at some than at others. To give one example, I also own the f/4 IS 70-200mm lens. At one point I tended to always switch to the shorter lens when shooting in the range up to 200mm, concerned about a potential sharpness hit with the 100-400. Over time I figured out that while the 70-200 is probably a very tiny bit sharper here, in most cases the difference in many kinds of shooting is insignificant and invisible in real-world output – and in many cases where I would have switched lenses I now leave the 100-400 on the camera. Continue reading Thoughts About the Canon EF 100-400mm f/4.5-5.6L IS Lens →

Commentary, Ideas, Photographic Myths and Platitudes

Photographic Myths and Platitudes – Primes Make You a Better Photographer

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(This is another in my series of occasional posts based on my replies to questions about photography that come up from time to time. This question was under discussion in an online photography forum, where the discussion began with a new photographer asking whether the acquisition of certain equipment would make him a better photographer. Those with experience in photography know the answer to this question, but it comes up, explicitly or implicitly, all the time, so I think it is worth another look here. The following text is a slightly edited and expanded version of my original answer. This is also part of my “Photographic Myths and Platitudes” series of posts. )

For the moment I’ll leave the full-frame question aside * – not that there isn’t a lot to say about it in the context of your desire to become a better photographer – and just respond to the following:

“My goal here is to become a better photographer. I feel zooms make me lazy, and that primes would make me think more about my photography.”

Sorry to say, but that is nonsense, plain and simple.

This notion that somehow primes are more “serious” than zooms comes up from time to time, and certain folks who post about photography (though not so often people who actually do a ton of photography) encourage this odd and unfounded line of thinking. I’ve speculated about where it comes from at times, and some of the following come to mind:

  • There is a certain mindset among some folks who desire to be viewed as artists that holds that being “different” is the most important characteristic of artists. (It isn’t, by the way.) And by doing something different, like using only primes, they may feel that they have established their different-ness from a world in which most others use zooms most often.
  • There is another notion that modern is not as good as “classic,” and therefore sticking to older equipment types is better. While there can be a risk of being too infatuated with new stuff just because it is new (perhaps the opposite form of gear obsession from the extreme of automatically dismissing the new) it just doesn’t make sense to automatically assume that, for example, because Henri Cartier-Bresson shot with primes that  you should, too. (HCB, by the way, did not choose the gear he used because it was “classic” – he chose the newly developed and quite modern small 35mm film cameras for a variety of reasons relating to his specific needs.)
  • There is also an odd notion that assigns an almost moral imperative to doing things the hard way, and that then presumes that those who do things in a more efficient or practical way must not be as serious as artists. Therefore, if shooting with zooms is “too easy,” shooting with primes must be better. This is often paired with the derisive advice to “zoom with your feet” or a claim that “zooms will make [you] lazy.” (Artists typically have no interest in making their work harder; they are generally far more concerned with making it better, and will use any tools or methods that accomplish the latter goal.)
  • Finally, there is the unfortunate notion, not unique to photography, that being “better” is largely the result of having the best or the “right” equipment – e.g., if I use this sort of camera or this sort of lens I will be more of an artist than if I use that camera/lens. The seed of truth in this – photography does require equipment – is too often built up into a false notion that photography is largely or even primarily about what gear you use.

The “zooms will make you lazy” business completely baffles me. Yes, folks doing point and shoot photography often may use a zoom that way, just zooming to get the shoot of their kids or the waterfall that most fills the frame, without bothering to move from their current position. But that fact that casual amateurs can use a zoom lens on their point and shoot cameras that way does not mean that the use of a zoom always means that this is the way one shoots. Continue reading Photographic Myths and Platitudes – Primes Make You a Better Photographer →

Publications, Reviews

Exposure for Outdoor Photography, by Michael Frye

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Exposure for Outdoor Photography by Michael Frye

Craft and Vision has just released Michael Frye’s new ebook, Exposure for Outdoor Photography. The book seems to be directed at the many folks who own DSLRs or non-DSLR cameras and are striving to advance beyond the point and shoot approach to their photography. The book takes a straightforward approach to some of the most important topics related to exposure. It begins with a basic description of, well, the basics of exposure – shutter speed, aperture, and ISO and some of the important terminology and concepts related to these factors. Michael keeps the level of detail to a minimum, but the basics are all there, including an explanation of the how and why of using the histogram display – which is probably just about exactly the right approach for his intended audience.

After getting the basics out of the way, the book moves to a series of ten “cases studies,” each of which uses one of his photographs to explore a particular aspect of exposure. The subjects of the case studies include using the histogram, dealing with both large and small depth of field, freezing motion or controlling motion blur, the tradeoffs of moving to higher ISO, recovering highlights in bright scenes, how to handle extremely bright highlights such as direct sun, and a nod to the zone system (in very simplified form) and HDR and exposure blending concepts. Rather than presenting the concepts in theoretical form, he uses his one photographs to provide practical examples for the case studies.

There are a number of things I appreciate about the book, and I think many readers may also agree:

  1. Rather than presenting rules that you must follow, Michael presents the concepts and explains/demonstrates the effects of some of the choice under discussion. He is careful to point out that there usually is no “perfect” exposure, and that there are different ways to get the result you have in mind. (Near the end of the book he even provides some examples of photographs that intentionally “violate” the exposure rules.)
  2. He strikes a good balance between too little and too much detail. He avoids the pitfalls of trying to make things so simple that they end up being simple-minded and of trying to cover all possibilities to the extent that many readers simply end up confused. This is probably an ideal balance for photographers who are taking first steps towards fuller understanding and control of exposure in their photographs.
  3. The case study photographs effectively illustrate the concepts that he covers. In addition, many of them are just plain fine photographs. (Two of my favorites are the Tuolumne Meadows photograph and one of geese in beautiful morning light.)

The ebook concept seems to be catching on quickly and there are plenty of good reasons for this. The visual quality of the text and illustrations is excellent. The books can be read on a laptop or a tablet. They are easy to purchase, and the cost is very low.

The book is now available from site affiliate Craft And Vision, and I understand that there may be a discount price during the first few days of availability.

G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more.
Blog | About | Flickr | Twitter | Facebook | Google+ | 500px.com | LinkedIn | Email

Text, photographs, and other media are © Copyright G Dan Mitchell (or others when indicated) and are not in the public domain and may not be used on websites, blogs, or in other media without advance permission from G Dan Mitchell.