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 The myth of the high F-stop: F16 and above

One mistake that even advanced photographers make

Jaro Kurimsky
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It’s quite often that you’ll see this kind of camera setting in a picture description of a landscape photography shot:

f/16 • 1/160sec • ISO800 • focal length 10mm • tripod •

or

Aperture f/14 | Time : 1/125s | ISO : 400 | Focal length : 18 mm | Tripod

Let’s analyse it first before we dig deeply into the matter. Here, we can see that:

  • The focal length is very short, meaning it’s set at a wide angle for capturing scenery and landscape.
  • The time is quite short. Considering the fact that both cameras were on tripods, it’s unnecessarily short; unless, of course, shooting was being done in a strong wind or during an earthquake.
  • The ISO is not on it’s lowest level

They do this because they believe in the myth that a high F. We know that higher F widens Depth Of Field, that’s the fact. Portrait photographer like extra narrow Depth Of Field to have blurred background behind the model, right? And landscape photographer wants extra wide one, correct? The main difference is that in Landscape photography the focal length of lens is very short and distance between camera and object is large. Would that matter? You bet! I invite you to have a look to real world example but before I have to point out one more thing.

Not many people realise that the performance of every single lens, in terms of Sharpness, Vignetting, and Chromatic Aberration, varies with the F-number you set on your camera. What does this mean in real life? It means that different F-numbers will give you different results. The results may be better or worse, but they will be different. Now, the question is, will wider Depth Of Field and higher ISO bring more overall sharpness into the picture than lower ISO and lower F, causing narrower depth of field? Let’s have a look first into how lens’s performance changes with the variation in F setting.

Here is an example of my favourite landscape photography lens for APS-C sensor Tokina 11-16 F2.8. Let’s look at the details.

Centre crop

F2.8 The base line
center dcs_4718

F5.6 Sweet spot
center dcs_4724

F10 Still good
center dcs_4729

F16 Loss of sharpness
center dcs_4737

F22 Lot’s of its peak sharpness gone
center dcs_4740

 

Corner

F2.8 Weak
-corner dcs_4718

F5.6 Better
-corner dcs_4724

F10 The best
-corner dcs_4729

F16 Drop in sharpness and vignetting
-corner dcs_4737

F22 Huge loss of sharpness
-corner dcs_4740

Almost invariably, every lens starts at a lower point than its best, improves with a few numbers up, and then reaches its sweet spot before it quite drastically falls. That’s the reality with most lenses.

Let’s take a look now at a real-world situation. Will F16 make close-distance objects sharper and result in more sharpness in the final product? I went to Bournemouth seafront to shoot real-life pictures to see if a higher F setting would bring more sharpness into the pictures. I placed my camera Nikon D7200 with Tokina 11-16 F2.8 lens on the tripod and pointed it towards Southbourne and Isle of Wright. Here are the pictures made with low ISO and low F against high ISO and high F:

Crops

Centre

1/400 sec; f/4.0; ISO 100
center dcs_4897

1/125 sec; f/16; ISO 1000
center dcs_4898

Corner

1/400 sec;   f/4.0;   ISO 100
-cornerdcs_4897

1/125 sec; f/16; ISO 1000

-cornerdcs_4898

You can see that at F22, the picture quality drops significantly against its sweet spot. However, is it really bad to shoot on a high F-stop? Here are two examples in which I used high a F-stop.

rays of sun on rocky beach
Bournemouth beach on Christmas day 2014

In this case, I used F22. It was really necessary because of the close proximity to the ground. About 40% of the picture shows objects in short distance with lots of details.  You can also see that the clouds are not very sharp. But at the end of the day, no one who bought this picture printed on canvas would ever complain about that.

the sun and clouds
The Sun above clouds, Tenerife, Spain

To take this picture, I had to go really far with restricting the light coming into the camera. I shot it at F45 and 1/8000 sec time with a 300mm lens. If you don’t have your ND filter with you, that’s all you can really do. Which reminds me, if you’re about to photograph the sun, don’t make the silly mistake that cost me £201.68. Read my article about this incident here.

sun-burnt-shutter
How (NOT) to take a picture of the Sun

 

From my experience, I always get the best sharpness under F8. In the following case, I used F6.3.

My Conclusion

To get the sharpest shot first, consider taking pictures in the sweet spot of F. In the case of my ultra-wide lens Tokina 11-16 f2.8, the sweet spot would be f4. If you are not sure about your lens, look at my blog post about looking for a lens’s sweet spot.  When the condition or technique requires go higher or lower than fine, go ahead but make sure you stay at the lowest ISO possible and stay closest to your lens’s sweet spot.

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