Achieve sharp images with wide angle lenses
March 31, 2011 40 Comments
With today’s high-resolution cameras, you are required to pay much more attention to how you shoot in order to get sharp images.
Focusing is harder than ever:
For wide angel lenses, the tolerance for when the lens is properly focused is extremely narrow. Often the tolerance for the autofocus system is not tight enough to get the most out of modern lenses. When using wide angle lenses, you can easily achieve extreme wide depth of field reaching from infinity to a few meters in front of the lens. The focusing just needs to be perfectly right – I call it the focusing sweet spot.
Use manual focus:
Test your lens to find and mark your focusing sweet spot. This will give you sharper and more consistent images. In doing this, you will sometimes find that the lenses you previously found disappointing now give you exactly what you want.
The examples above is a 200 % zoomed view of an image which was shot from my office window, and you can see just how big a difference it makes when you use the lens focusing sweet spot compared to just using the autofocus system. This example is made with a Canon Zoom at 17 mm. but could have been made with most other wide angle, primes as well as zoom lenses.
Find your focusing sweet spot
The easiest way to find the focusing sweet spot is to shoot tethered, as you get immediate feedback on how well you are focusing. With Canon and Nikon cameras, you will have tethered functionality directly in Capture One 6 Pro. With other camera brands, you can use Capture One´s hot folder functionality to get your images into Capture One by using a vender specific program for shooting tethered.
Steps for finding the focusing sweet spot:
- Ideally, find a location where you can focus on infinity where you have objects all the way from infinity to a few meters from the camera.
- Place your camera on a steady tripod
- Make sure to turn off any image stabilization as this may influence the sharpness from shot to shot.
- Set camera on manual focus
- Set the lens to full open.
- Shoot a series of images where you sweep through a range of focusing positions near the focusing point for infinity. For each image, check if you have better sharpness in the center of the image at a zoom level of 200-400 %. Once you have achieved maximum sharpness mark this point on the lens with a pen.
On this zoom lens, I have marked the position for the best focus on infinity.
Steps for finding the aperture that gives you the best compromise between sharpness and depth of field:
- Set focus on the marked position for maximum focus on infinity
- Take an image at each aperture step.
- Compare the images side by side to see the effect of stopping the lens down. In Capture One Pro 6, you can simultaneously zoom into a maximum of 12 images. Doing so is a big help for this analysis
Typically, you will see that you get the best sharpness at 1-2 f-stops from full open. Stopping further down may lead to softer images in the center. You should also check the edges and objects closer to the camera. For very vide angle lenses like 10-20mm, the depth of field is extremely deep even for apertures like 5.6 and 8 and stopping further down may not give you an increased depth of field as the whole image may just become softer.
With the lens set at best focus for infinity, I shot at each full aperture step. Above are a 200 % zoomed view of the centers of the images. At f5.6, the image is at its sharpest, but the range from f4-11 also works well. At f16 and f22, the image sharpness decreases dramatically.
The images above show a 200 % zoomed view of a car half way between “infinity” and the camera. Contrary to what one might expect, the increased f-stops doesn’t give a greater depth of field. As the lens is stopped down it just becomes softer and softer. Again the image is actually most sharp at f5.6.
Setting the sweet spot – Optimizing focusing for the best aperture:
My goal is to be able to achieve the sharpest possible image from infinity to as close to the camera as possible. With the lens stopped down will my initial focus mark on the lens still be the best compromise? My experience is that for most wide-angle lenses, primes as well as zooms this is actually the best compromise, but to be absolutely sure, we need to check it out.
Set the lens at your mark for the best focus for infinity.
- Take some shots where you focus slightly closer than infinity.
- For each shot, check if you get a better compromise between best sharpness at infinity and the deepest depth of field.
- Mark the lens with a pen at the point where you have the best compromise.
Now you have found the focusing sweet spot for the lens. Next time you need maximum sharpness and maximum depth of field, set your camera to manual focus and use your sweet spot mark on your lens. Doing this, you may achieve sharpness you may not have thought possible.
Hi Niels
Thank you for sharing this great tutorial.
Andreas
Great information thanks for sharing it. I will pass it on!
Interesting and surprising. Will go for the focusing sweet spot. Thank you.
Thanks for your explanations, its very usefull. But so hyperfocal tables are useless? It is necessary to test each lens? Thanks.
Thank you for sharing – I have to check my lenses…
Hello Neils,
I shoot a Sony A850. Walter Borchenko noted on his C1Pro tutorials that the Focus Mask in C1Pro is optimised for Phase backs—no AA filter—and that some DSLRs may need to have the Focus Mask adjusted to reflect this (shots seen on screen can be sharp, but the Focus Mask does not show the plane of focus). This is what I have found. The A850 can’t shoot tethered directly, as you know, but the hot folder setup works well.
Can you suggest a method that will allow me to adjust the parameters of this tool (Focus mask) so that it does show the plane of focus properly? Thanks in advance, Kit
Same for me shooting with A850. I was wondering why the focus mask indicator did not seem to match what I thought was in focus on some of the shots. great information about the sweet spot as I was also under the mistaken impression that stopping down lens will increase depth of field.
It is useful information.
Thank you for sharing the great information.
Your information is always very good to me.
Users of a range of Canon cameras may want to adjust the Microfocus for their lenses. This is performed and ‘remembered’ on a per lens basis by the body. Just Google “canon micro focus adjustment” and you’ll find out how.
Its been suggested that there is an official How To guide by Canon but I’ve never found it.
Wenn so getan wird, als sei dies nur bei Weitwinkel so, dann irrt dieser, nur die Distanz ist bei anderen Optiken evtl. geringer! Dass dies “geheim” und neu ist, kann ich nicht glauben, dies ist schon immer so gewesen, siehe frühere “analoge” Objektive, die diese “Listen” noch an der Einstell-Scala Blende/Entfernung haben. Weisheit eines Professors? Leider nur Lektion 1 Fotokurs Elementarstufe.
L’abitudine a controllare sul vetro smerigliato o a ragionare sul fuoco in base a parametri di vecchio tipo non passa, ancora oggi anche quando uso l’autofocus sulla fuji s5 o nelle prove che ho fatto con phase one confronto i dati dell’autofocus con il mio pensiero e le mie valutazioni ad occhio
Unfortunately the display and the viewfinder of some “consumer” DSLR is not that wide and bright to asses the focussing. Also: ever tried getting manual focus on a EF17-40 4L ? I love this lens, but the focussing wheel has such a short span that it is really difficult to fine-adjust. I think it was really designed with AF in mind…
Very informative one to attain such vivid and much clearer pictures.
Thanks for posting this! Something I thought doing since a too long time without really doing it. It’s the micro-adjustment for static, landscape subjects.
Andy, I use the Datacolor Spyder Lenscal device to micro-adjust my Canon camera-lens combination and the device comes with an easy to understand explanation about how to do it. Highly recommended and it’s not that much magic to do.
Klasse Infos auf jeden Fall gut gemacht.
lg Frank Hedrich
Pingback: Photography through the lens cap « The Image Quality Professor's Blog
Hello,
I was really impressed by the video of the volvo campaign,
i do have a P65+ and 645df
how do i process the images in capture one
i mean how do i combine the 30 images into one single one.
Please let me know ?
thank you.
As a wedding and family portrait photographer, this information helps greatly. I hate it when the sharpness is at the ears, instead of the eyes, even though I focused on the eyes. Or, when some in the group are sharp, and others are soft, even though I should have enough depth of field.
This sounds more like a AF micro adjustment (camera/lens) issue than a DoF problem. I have adjusted my Nikon D3 & lenses for this. Regardless if I manual focused using the viewfinder indicator arrows, the AF fine tune was a necessary adjustment.
Thanks for great post Niels V. Knudsen! This blog is the most helpful photoblog I have ever found. Capture One user my self, I do recommended it to any photographer, even not Capture One users.
Glad to hear that you guys like the tip,
All the best,
Niels
Strange how you can invent a new term, deny conventional wisdom, and people love it !
Yes, if you stop down too far, diffraction will reduce the maximum sharpness. But that doesn’t mean it doesn’t increase the depth-of-field. DOF is the range of distances that are acceptably sharp. If you stop down so that nothing is acceptably sharp, that’s bad technique.
You have rediscovered the ‘optimum aperture’, where you have stopped-down enough to give low abberation, low diffraction and greatest depth-of-field.
You have rediscovered the hyperfocal distance where ‘acceptable sharpness’ extends from infinity to a point as close as possible.
Nothing new.
Eureka!!!
This is exactly what I was thinking. Back in the 80s i was using the lens scale (remember them!) on my Nikkor 50mm 1.8 allied to my f-stop setting to evalluate the hyper focal setting as it is better known as.
Obviously you could not see the results on your rear screen as there was none. So you had to ‘know’ what you were doing to acheive the result you wanted, and what would come back from the film processors.
As you say nothing new at all.
It has much to do with modern auto focus technology that one assumes as the ‘only way’,
and peoples lack of proper photography technique / knowledge.
Bring out the manual focus FE and do it the right way!!!!
Mr. Knudsen didn’t invent new terms and didn’t deny conventional wisdom. He reminded us good old rules, nothing new but very useful. People love it simply because it helps.
What do you think car producers put that annoying ding ding ding acoustic security belt signal for??
Keep on Mr. Knudsen and thank you!
No, these are not new things. However, it seems this is more the ‘focus at infinity’ technique rather than the hyperfocal point method. I generally prefer to focus at infinity for landscapes. Hyperfocal method is a bit different. With the hyperfocal method, you would focus at some point in the mid-ground.
Simply turning the focus ring to the infinity mark doesn’t always give satisfactory results. If you choose to use ‘focus at infinity’ versus hyperfocal, it is good to know this.
The focus at infinity technique isn’t as popular as the hyperfocal method, I think. While it is not knew, I don’t think it is as widely discussed… Nice to see it presented.
I prefer to focus at infinity because I find infinity-class stuff (things far away) to be more clearly defined than when I use the hyperfocal method. Also, I find near-ground stuff to be just about as sharp using focus at infinity as with hyperfocal method. I do tend to use a smaller aperture than f/5.6, though, while still respecting diffraction effects. f/8 or f/11 on APS-C. Maybe f/13.
Beware that the best (sharpest) focus position for infinity can change with time, due to temperature variations in the body of the lens.
Yes but is fantastic when you use a back on an old SWC, where you have only your eyes and the depth of field to calculate the real focusing
Please do it in French!
L’experience de fair les photo sans automatisme e de regleèè unne camera ancienne e special comme la SWC çest unique e regardèe les images sur le mac fait aveq ça experiance magnifique
Hi,
Brilliant tutorial, really getting into the nitty gritty of taking a good photo but keeping it simple! I’d noticed an old 28mm prime manual lens that focussed to infinity after 3.5m was always just a bit sharper if I focussed to infinity and backed it of just a touch. This validates the technique for me and now I’ll be sure to check out its best f-stop range as well in Capture One 6 Pro!
Besten Dank. Ihr seid super. Gibt es das ganze in deutsch? Weiter so, toll. Danke.
thank you for tutorial and comments. I am unable (as far as I’m aware) to mark the sweet focus spot on my lens as there are no numbers or indicators on the lens! I guess I will just have to shoot a series of images around infinity focus at f4 and f5.6 and select the most successful image in post-production stage. But I learned just as much from comments as I did tutorial. Great page!
An other classical way to see the DOF stuff is the 1/3; 2/3 rule leading to similar practice :
The depth of the sharp zone field is not centered on the point that is focused at, but spans one third before the Focus Point… and 2 thirds in the back after the FP.
So there are a lot of situations where a shortening of the focus distance (compare to the “more precise” one in the viewfinder) will either suit the optical DOF better to capture scenery, or spare some DOF by realocating the part of its range redundant at infinity.
But the topic of this tutorial is a bit different and sharper than this general law when it comes to experimenting a particular lens, with a little work to do.
Great article, but for real life situations, I agree with Greg HL. Make 2 marks: One for infinity @ open aperture, and then another one, for maximizing depth of field from infinity to foreground at the aperture most used (e.g.f8 or f11). This means, the focus point will be slightly closer, than the infinity mark.
Nice Post. Things that you know, but it’s nice to be so graphically reminded. We forget.
Tom
Getting sharper pictures in a wide landscape is quite difficult and you need to be very precise in order to get a sharp picture from a wide angle lens. Your tips are really useful Thanks a lot!
Since the admin of this website is working, no doubt very quickly it will be
renowned, due to its feature contents.
Pingback: Achieve sharp images with wide angle lenses | The Image Quality Professor’s Blog | DTEK Systems Uk
I think everything said was very logical. But, think about this,
suppose you added a little content? I ain’t saying your content isn’t solid.
, however what if you added a post title that makes people desire more?
I mean Achieve sharp images with wide angle lenses
| The Image Quality Professor’s Blog is kinda plain. You might look at Yahoo’s front page
and note how they create news headlines to grab people interested.
You might add a video or a related picture or two to grab people interested about everything’ve got to say. In my opinion, it might make your posts a little bit more interesting.
Hi Stefanie,
Thanks for your comment. We are always trying to find the right balance between professional, descriptive AND appealing, attention grabbing subject lines and headlines. Your comment is noted and we will continue to try to find the right balance in the future.
All the best,
Niels