# Problems focusing sharp -- Discussion



## NedM (Dec 31, 2013)

Every now and then I receive a lot of portraiture sessions from clients.
When I do, I always stick to my EF 50mm f/1.8 II aka "nifty fifty".

This lens has really great glass and the build quality isn't too bad either.
But every time I take this little lens out for a session, I'm always seeing in post-processing that the focusing was always off or near what I wanted it to be.
For instance, I focused on her nose and the rest of image is very soft.

Would increasing my f-stop number gradually cause the image to be sharper?
I don't quite understand the concept between the f-stop and how it affects my sharpness in an image.

I'm tired of losing tons of great photos just because my focusing was off or not sharp.


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## ronlane (Dec 31, 2013)

Are you shooting it at f/1.8? Most lenses have a "sweet" spot where they are sharpest. I cannot find it now but on Cambridge in Colour - Photography Tutorials & Learning Community, I thought there was a test to determine sharpness.


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## runnah (Dec 31, 2013)

1.8 is going to produce a shallow DOF. Depending on other factors a subject's nose maybe be sharp and her eyes may not be, this is normal. The fstop, distance to object and the focal length all determine the DOF.


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## NedM (Dec 31, 2013)

ronlane said:


> Are you shooting it at f/1.8? Most lenses have a "sweet" spot where they are sharpest. I cannot find it now but on Cambridge in Colour - Photography Tutorials & Learning Community, I thought there was a test to determine sharpness.



When I first bought the lens I realized shooting on f/1.8 resulted in very soft images and nice bokeh background.
I wanted sharper images with lots of detail, so I started increasing f-stop to around f/5.6 and it worked!
The only problem is sometimes my place of focus is so narrow that I end up focusing on the bridge of the nose of a subject rather than their whole face.

How do achieve this kind of focusing?


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## NedM (Dec 31, 2013)

runnah said:


> 1.8 is going to produce a shallow DOF. Depending on other factors a subject's nose maybe be sharp and her eyes may not be, this is normal. The fstop, distance to object and the focal length all determine the DOF.



So be able to control the f-stop, distance and focal length would grant me better control on my focusing?
Let's say, I wanted to be able to a subject's face in focus and sharp. How would I be able to do that with such a lens?


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## runnah (Dec 31, 2013)

NedM said:


> runnah said:
> 
> 
> > 1.8 is going to produce a shallow DOF. Depending on other factors a subject's nose maybe be sharp and her eyes may not be, this is normal. The fstop, distance to object and the focal length all determine the DOF.
> ...



Since you cannot control the focal length, you have to change either your distance or fstop. Shooting a headshot with the 50mm you should be around 2.8 range depending on light.


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## ronlane (Dec 31, 2013)

In your introduction you say that you run your own photography business, and you are asking questions like this???


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## SCraig (Dec 31, 2013)

Calculate the depth of field before you shoot.  Try here: http://www.dofmaster.com/dofjs.html


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## Derrel (Dec 31, 2013)

NedM said:


> Every now and then I receive a lot of portraiture sessions from clients.
> When I do, I always stick to my EF 50mm f/1.8 II aka "nifty fifty".
> 
> This lens has really great glass and the build quality isn't too bad either.
> ...



Yes, increasing your f/stop's "number" is traditionally called "stopping the lens down", meaning going to a higher number value, which stops the len's iris diaphragm DOWN, to a physically smaller hole. If the nose is in focus, but the rest of the face is out of focus, you need to stop the lens down, to an f/strop like f/5.6 or f/6.3, thereabouts.

The wide apertures, like f/1.8 and f/2 and f/2.8 create shallow depth of field, and allow you to blur the background zone easily,

Medium apertures, like f/3.5 to f/5.6 are where most lenses are at their SHARPEST, and BEST optically. There is more depth of field than with wide apertures, but less than with small apertures.

Small apertures, beginning at f/6.3 and going to f/32, have a lot of depth of field. In portraiture, I often use f/6.3 or f/7.1 with telephoto lens lengths like 85,100,135,or 200mm. Using a 50mm lens at f/8, you get pretty deep depth of field once the lens is focused past 20 feet.

At CLOSE DISTANCES, there is not a whole lot of depth of field with a 50mm lens, no matter what the f/stop is set to.


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## NedM (Dec 31, 2013)

ronlane said:


> In your introduction you say that you run your own photography business, and you are asking questions like this???


There's nothing wrong with learning more about the equipment you own and operating a business. Either you're here to help or not.


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## 480sparky (Dec 31, 2013)

NedM said:


> ..........Let's say, I wanted to be able to a subject's face in focus and sharp. How would I be able to do that with such a lens?



You'll need to do a little DOF math first.  Start with how far you are from your subject, and what aperture you'll be using.  A DOF app will give you a rough indication of how deep your DOF is going to be.  The next step will be to place your focus point at the right distance so the DOF covers the face of your subject.  If the AF doesn't put it where it needs to be, you'll need to over-ride it.


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## NedM (Dec 31, 2013)

SCraig said:


> Calculate the depth of field before you shoot.  Try here: Online Depth of Field Calculator


This site is going to help a lot, thank you SCraig!


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## ronlane (Dec 31, 2013)

NedM said:


> ronlane said:
> 
> 
> > In your introduction you say that you run your own photography business, and you are asking questions like this???
> ...



I never said there was anything wrong with learning more. I think that I am helping by asking that question. If you are producing images that are soft and selling them to clients, you are running the risk of hurting your business in the long run by risking loosing repeat customers.

The viability of a business rely's on satisfied customers that will be repeat customers and who will refer you to new customers.


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## NedM (Dec 31, 2013)

Derrel said:


> NedM said:
> 
> 
> > Every now and then I receive a lot of portraiture sessions from clients.
> ...



Yes! This is an answer that I was exactly looking for!
I knew lenses individually had their own 'sweet spot' I just wasn't how or why they did.
You explained what I needed to know very thoroughly and with lots of information!
I just need to study up more how focusing works.
Thank you, Derrel!


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## NedM (Dec 31, 2013)

ronlane said:


> NedM said:
> 
> 
> > ronlane said:
> ...



I don't give any of my clients images that are not sharp or high quality. I just noticed in post-processing that some of my images were not focused or sharp enough for me to give to my clients. So, naturally, I wanted to know why and what I could do to prevent this from happening over and over again. Thank you for your input, I appreciate it!


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## Designer (Dec 31, 2013)

For future reference, Ned, you should focus on your subject's eyes, not the nose.  So let's say that your DOF is a total of 1.29 feet at f2.8.  Focusing on a person't eyes should make the whole face in focus with your 50mm lens.  Any wider, and you just don't have the depth for a person's face.  Good luck!


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## NedM (Dec 31, 2013)

Designer said:


> For future reference, Ned, you should focus on your subject's eyes, not the nose.  So let's say that your DOF is a total of 1.29 feet at f2.8.  Focusing on a person't eyes should make the whole face in focus with your 50mm lens.  Any wider, and you just don't have the depth for a person's face.  Good luck!


Thank you, Designer! I'll be sure to keep this in mind when I am out shooting portraiture.


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## KmH (Dec 31, 2013)

Moved out of the Photography Beginners' Forum.

The Canon EF 50 mm f/1,8 II is a consumer grade lens that delivers garbage bokeh because of it's amazingly poor build quality.
Though the background is blurred from a shallow DoF, the quality of that blur - the bokeh - sucks with that lens.
A big part of the problem with the jittery, nervous looking, 5 sided bokeh the lens produces is the low number of lens aperture blades (5), and the aperture blade straightness and sharp edges.

IMO, the Canon 50 mm f/1.8 II is not a lens suitable for making client photographs.


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## NedM (Dec 31, 2013)

KmH said:


> Moved out of the Photography Beginners' Forum.
> 
> The Canon EF 50 mm f/1,8 II is a consumer grade lens that delivers garbage bokeh because of it's amazingly poor build quality.
> Though the background is blurred from a shallow DoF, the quality of that blur - the bokeh - sucks with that lens.
> ...



Your opinion matters, thank you for your input.
Which lens do you believe to be suitable for making client photographs?


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## ronlane (Dec 31, 2013)

85mm f/1.8, 100mm, 135mm, 70-200mm f/2.8 (mayb f/4 also) and the 24-70mm f/2.8 are all popular lenses.

The most popular are the 85mm and the 70-200mm


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## NedM (Dec 31, 2013)

ronlane said:


> 85mm f/1.8, 100mm, 135mm, 70-200mm f/2.8 (mayb f/4 also) and the 24-70mm f/2.8 are all popular lenses.
> 
> The most popular are the 85mm and the 70-200mm



I suppose since I have a crop sensor camera with my 50mm, I won't be needing an 85mm anytime soon. 
Although, I am working on getting an 70-200mm.


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## ronlane (Dec 31, 2013)

NedM said:


> ronlane said:
> 
> 
> > 85mm f/1.8, 100mm, 135mm, 70-200mm f/2.8 (mayb f/4 also) and the 24-70mm f/2.8 are all popular lenses.
> ...



No, the 85mm with a crop sensor is a great length for portraits. All the ones I've listed work well and are popular with crop and full frame.


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## orljustin (Jan 1, 2014)

NedM said:


> Every now and then I receive a lot of portraiture sessions from clients........
> 
> Would increasing my f-stop number gradually cause the image to be sharper?
> I don't quite understand the concept between the f-stop and how it affects my sharpness in an image.
> ...



How do you have a photography business, doing 'a lot of portrait sessions' and not know what changing your aperture does?   Weird.


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## KmH (Jan 1, 2014)

ronlane said:


> NedM said:
> 
> 
> > ronlane said:
> ...


I agree completely with Ron.
When I still had the studio open I rarely used a 50 mm lens to make portrait shots and mostly used 135 mm to 200 mm focal lengths. For some groups I used 300 mm.

I used the longer focal lengths for a couple of reasons.
A primary reason was clients are more relaxed with the camera being further away, and well outside what they perceive as their personal space.
Reason 2 relates to DoF, and from your post about photographing star trails it's apparent you don't yet understand DoF.
DoF is likely the single most difficult technical aspect of doing photography new photographers have trouble coming to grips with.

A 50mm lens on a crop sensor (1.6x) camera, with its aperture set to f/4 and the point of focus at 10 feet ha s total DoF of 1.84 feet.
A 100mm lens on a crop sensor (1.6x) camera, with its aperture set to f/4 and the point of focus at 20 feet has total DoF of 1.83 feet. Pretty close to exactly the same total DoF as above.

Since focal length doubled from 50 mm to 100 mm, to keep the same subject scale in the image frame the camera has to be 2x further away from the subject.
Plus, blurred background elements are magnified by the 100 mm focal length when compared to the 50 mm focal length, making the blurred background the 100 mm lens produced look more blurred but it really isn't.

The apparent blurrier background the longer focal length provides explains my reason #2 above.


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## NedM (Jan 2, 2014)

orljustin said:


> NedM said:
> 
> 
> > Every now and then I receive a lot of portraiture sessions from clients........
> ...



I've been able to cope with what I know.


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