Subject isolation: wide aperture or postprocessing?
"Fast" lenses with wide apertures are good for low light and subject isolation. I want to focus on the later one. Suppose the amount of light is NOT an issue.
How would you compare photos taken with wide aperture vs a smaller aperture and then the background blurred in postprocessing?
- Clearly, postprocessing will take longer. So, if you do it often and you are paid for it lenses like 24 f/1.4 could be justified.
- On the other hand, blurring can be done selectively. Instead of taking a picture at f/1.4 and slightly missing the focus on the eye, one can take the same picture at f/4 and blur the image in post.
What other issue do you see?
Is it a good idea to take the same photo at wide aperture for a chance to get the image right in camera and then at smaller aperture to have more info just in case the first one was a bit of? Or is this a waste of time?
#1. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 0
ron917 Nikonian since 14th Dec 2012Thu 28-Nov-13 04:05 PM
Blurring in post processing often looks fake to me. It may possible to make it look more like the result of actually shooting with a wide aperture, but I see a lot of images where the blur was obviously added in post.
#2. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 0
agitater Nikonian since 18th Jan 2007Thu 28-Nov-13 04:30 PM
>What other issue do you see?
Selective background blurring is easy enough to do, but it is not the same as large aperture lens bokeh. Simulation of lens bokeh - a quality which varies from lens to lens - is really difficult to do in post. IMO, bokeh - the natural qualities of an out-of-focus background as rendered by a specific lens - is almost always better when captured in the camera rather than manufactured in post.
>Is it a good idea to take the same photo at wide aperture for
>a chance to get the image right in camera and then at smaller
>aperture to have more info just in case the first one was a
>bit of? Or is this a waste of time?
I think that whenever possible, getting a second almost identical shot of a subject at a significantly different aperture or exposure setting is always a very good idea.
#3. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 0
walkerr Nikonian since 05th May 2002Thu 28-Nov-13 04:56 PM
I agree with the others. Although I don't blur my own images in post-processing, I've done it for others using the better plug-ins out there. It's very hard to get a realistic transition from in-focus to out-of-focus, and it takes some time, even with the best masking tools. I've never been satisfied with the results, which is why I don't do it for my own images. On the other hand, the people I've done it for were happy, but I was rescuing some frankly awful images. They had nowhere to go but up. I personally view it as a last ditch effort when you have no other choice, rather than a primary plan. All that presumes that you want a look that resembles a fast lens with limited depth of field. If you're going after a Lens Baby look or one that is clearly post-processed (which some photographers do), then post-processing is fine and even easy.
As for whether or not fast lenses are worth it, I don't think it has to with whether you're paid for it or not - it's whether or not you feel the expense is worth it. If you enjoy the lenses and can afford them, great. It's however you choose to look at the decision. Keep in mind that there are a nice set of less expensive fast lenses, too. Nikon's 28mm 1.8, 35mm 1.8 (for DX), 50mm 1.8, 85mm 1.8 are good examples that perform very well and are substantially less than their 1.4 counterparts.
#4. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 0
esantos Nikonian since 10th Nov 2002Sat 30-Nov-13 07:10 PM
Trying to simulate bokeh in post processing can have its problems. While a simple Gaussian Blur is okay in some situations I have found that the specialized Photoshop plug-ins are a little better. Is this simulated blur better than the real thing from something like the famous "Cream Machine" Nikkor 85mm f/1.4? No, no way. Regardless, here are a couple of guidelines that I find useful in increasing your odds in post processing and when shooting with a slower lens.
* It's really important to try to isolate your subject from the background. And by that I mean if at all possible situate the subject at least six feet or more away from the nearest background objects that will be showing up in the frame. If anything the distance will hopefully fall outside of the DOF of your lens and aperture setting.
* If you can't extend the background out then try using a lens with more focal length putting you farther away from the subject and thus moving the the back end of the DOF range closer to the subject.
* In post processing try using different strengths of blur in layered masks to help create the illusion of depth. A single level of blur throughout the background will looks less believable than gradual blur from fore to aft. You can also use lighting techniques to highlight areas of the background to also give a little bit of variance to the overall luminance of the background another technique to fool the eye/mind. Vincent Versace uses this to great effect. If you want to learn more on how to do this I recommend his book Welcome to Oz.
esartprints.com Ernesto Santos Photography
#5. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 4
vitalishe Nikonian since 27th Dec 2012Sat 30-Nov-13 07:34 PM
Thank you for the suggestions. It all makes sense. I think I should play a bit with preprocessing to see what are the differences between the post and the real thing. So far, the concensus deans to be that in post it is very hard to do quality blurring.
I have to disagree with one thing. In my experience with the depth of field calculators the depth of field is virtually independent of the focal length of the lens so long as the subject is filing the same portion of the frame.
Shooting with 50mm lens at f/2.8 from 1m away you get .94m and 1.05m as the limits forthe depth of field of .09m.
Shooting with 100mm lens at f/2.8 from 2m away you get 1.94m and 2.05m as the limits for the same .09m depth of field.
So, if you want the subject to fill the whole frame and you know that you want a specific aperture (say f/2.8) you will get the same depth of field with any of the trinity lenses. There will be other differences, but not in the depth of field.
#6. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 5
Ineluki Nikonian since 03rd Aug 2011Sat 30-Nov-13 07:39 PM
A good photoshopper can blur everything in the bg and no one will see the pp.
#7. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 6
briantilley Nikonian since 26th Jan 2003Sat 30-Nov-13 08:32 PM
Hmm - if Rick and Ernesto (both of whom are very "good photoshoppers") would prefer to achieve the effect with a good fast lens at the time of shooting, that's good enough for me
#9. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 5
Ferguson Nikonian since 19th Aug 2004Tue 10-Dec-13 01:34 AM
>I have to disagree with one thing. In my experience with the
>depth of field calculators the depth of field is virtually
>independent of the focal length of the lens so long as the
>subject is filing the same portion of the frame.
Yes, but no. Isolation is not just about DOF.
Even though the DOF is similar, WHAT you see in the background changes significantly based on focal length, so the in-focus portion may look the same, but the out-of-focus part will be different subjects, since your field of view is (approximately) half or twice.
The result for me is that mostly, longer lenses achieve greater isolation as they ALSO show a smaller portion of the background, so distracting and uninteresting items are not only blurred, but often off-frame.
PS. Someone, somewhere may be able to blur background and make it indistinguishable from shallow DOF, but I know I sure can't -- it always looks grossly fake. If you are good at it, great. Post some samples to compare though.
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#11. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 9
sabbey51 Nikonian since 10th Jan 2010Wed 11-Dec-13 12:32 AM
I have to agree with Eric. I've lately been using contrast, saturation, etc very successfully. The LR select brushes provide a very natural transition.
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#8. "RE: Subject isolation: wide aperture or postprocessing?" | In response to Reply # 0
The out of focus areas look very different if you use DOF rather than post processing. It's not just that they are out of focus, it's the shape of out of focus elements. Using DOF, the out of focus elements are more rounded with smoother transitions. Using software, they tend to be soft but not round.
It depends a little on what effect you want. An angled subject is very demanding because you have degrees of out of focus. A square subject is easier since you have clear in focus and clear out of focus areas.
If you are trying to manage background areas, don't limit yourself to just focus. You can get great results by using reduced contrast neutralizing light and dark areas, and neutralizing color differences.
The same idea goes for sharp areas - sharp areas look sharper if the transition areas are a little soft.
If you shoot at f/4 rather than f/1.8, it's very hard to create the gradual transition you would get by nailing focus at f/1.8. If you miss focus it becomes even harder since you have to take sharp areas and create degrees of out of focus areas.
Here are two examples. The first used post processing and shallow DOF while the second used just DOF. Both were with a 600mm lens and Nikon D800E.
This used the 600mm lens shot near wide open at 15-18 feet, but the background was close and very busy. I used a number of layers of blur, contrast, color, and brightness to manage the background and the subject.
This was pretty much straight from the camera. It was shot with a 600mm lens at a wide open aperture with a long lens at a distance of around 70 feet. Software could have been used here for the mother but not the hammock, and I needed the light of a wide open aperture.
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