Beginner Achieving Great Bokeh (but Subject is Blurred)

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#1
I've just upgraded from the Nikon 18-55mm kit lens to a 50mm f1.8G.

I went out to take a few test shots earlier and was getting great background bokeh at 1.8 f-stop.

However, I took a test shot of my friend and upon pulling the image into Light Room, when zooming in, it was obvious that their face wasn't sharp (slight blur).

I shot in full manual mode with a fast shutter speed (my hand was steady too so I'm discounting hand shake).

Does anyone have any ideas why this may have happened?

To put the distance into perspective, you could see my friend from the thighs up.

Could it be that I was too far away or the shutter speed was off, causing blur?

Any ideas would be appreciated!
 
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#5
Thanks for the responses.

Now I think about it, I think I may have forgotten to set my single focus point.

If this was off target, I imagine this would cause the face to become out of focus?

Also, I assume f1.8 is quite a 'danger zone' with the risk of hand shake?
 
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#7
Thanks for the responses.

Now I think about it, I think I may have forgotten to set my single focus point.

If this was off target, I imagine this would cause the face to become out of focus?

Also, I assume f1.8 is quite a 'danger zone' with the risk of hand shake?
Possibly but it’s an easy lens to use, just go and practise, I used pegs/posts/gateways, anything really to get used to the shallow focus range and also you get chance to see the difference between the F numbers.
 
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#8
Thanks everyone, the advice has definitely been taken on board.

Looking forward to getting out to keep practicing with this lens!
 
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#9
It's not just about hand shake, if you imagine that the plane of acceptable focus is maybe an inch deep (for example), you or the model only have to move a tiny bit for things to get out of focus.

You will find that things move a lot if you press the shutter for focus and then wait a few seconds, you need ton constantly refocus on the bit you want in focus and release the shutter promptly.
 
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#10
Thanks for the responses.

Now I think about it, I think I may have forgotten to set my single focus point.

If this was off target, I imagine this would cause the face to become out of focus?

Also, I assume f1.8 is quite a 'danger zone' with the risk of hand shake?
drop the image into Capture NX and it will show you the focus point, I don't use it much but for finding if you nailed the point it is ideal.
 
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#11
This may well be a focus point or general AF issue but you do have to use a good steady technique to eliminate yourself as a possible cause of problems and give the kit a good chance of success :D I've seen people move their head as they press the shutter button and a little nod forward or back could cause the body and camera to move and be enough to cause a problem when you look at the picture closely.
 
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#12
Could be pilot error or an af fine tuning issue.

Firstly set the camera on a tripod using manual focus and no vr and self timer take a photo of a coke can or something similar and if you can get sharp results then thatsgood news. Then start to eliminate other issues one by one.
 
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#13
@ClickClick87
Where you say this "To put the distance into perspective, you could see my friend from the thighs up"

Were you by any chance focusing on the subjects eyes but then recomposing to get more of their body in the frame??? If so then that is likely a primary reason for the issue......as noted above by others 'in effect a movement after focusing....' if you lookup "focus & recompose" you will find both good explanation as to why it can cause an issue but also others that say fine go ahead. But as context is all ~ it needs understanding of the pitfalls to use it wisely.

All the best with practicing and learning & enjoying the lens and it's bokeh with narrow DoF.
 
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#15
Thanks for the advice and comments on this.

I have a sample image I'd like to upload and discuss (a very boring composition that I just shot as a test) but my file size is too large at 1.4mb (exported from LR).

Could somebody please advise the best way to get this uploaded without losing quality of the image?
 
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#16
Thanks for the advice and comments on this.

I have a sample image I'd like to upload and discuss (a very boring composition that I just shot as a test) but my file size is too large at 1.4mb (exported from LR).

Could somebody please advise the best way to get this uploaded without losing quality of the image?
I would image most of the images posted on here will be 200K or less ........ you don't need to post "big" files for discussion
 
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#17
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#18
Thanks for all the advice.

Okay, here is the image. I had to email it to myself and screenshot it so I apologise if it comes out extremely small.

As a test, I grabbed the first thing I found (a can of deodorant...boring, I know!)

AF wanted to focus on the background so in manual focus (no tripod), I aimed the very right-hand focal point on the 'Right Guard' logo, I took this shot.

Although nowhere near as bad as the photo I mentioned in my original post - I have a problem with the can toward the left side of the photo. The bokeh seems to spill into the can (is this due to the rounded shape perhaps?). Also even though I focussed on the logo, its not overly sharp to me.

Of course I've done some subtle post production in Light Room but nothing that I can imagine resulting in image loss.

1/2000s at f1.8 ISO 200 if it helps!
 

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#19
I would say while learning, stick the can dead centre and use centre single focus point, you could add cans just behind the centre, left and right (this will give you an idea of DOF or the shallow focus point you will have.

Just experiment a few times and move closer/further away and you’ll start to see certain things happening.
 
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#20
I would say while learning, stick the can dead centre and use centre single focus point, you could add cans just behind the centre, left and right (this will give you an idea of DOF or the shallow focus point you will have.

Just experiment a few times and move closer/further away and you’ll start to see certain things happening.
That sounds like good advice! As I look at that photo more, I can already see subtle things like the back of the table being swallowed up by the bokeh so hopefully I can get the hang of finding out where I need it to be fairly quick.

Will definitely get back out in the garden tomorrow to shoot a few DoF try outs.
 
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#21
Manual focus isn’t very reliable, especially at shallow DoF. Easy to move the camera and it requires your eyes to be 100% too. This shot looks slightly front focussed.

To really check you need a tripod (or just put the camera on something solid) and focus on an object, then use live view to do the same and see if the images are as sharp as each other.
 
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#22
Manual focus isn’t very reliable, especially at shallow DoF. Easy to move the camera and it requires your eyes to be 100% too. This shot looks slightly front focussed.

To really check you need a tripod (or just put the camera on something solid) and focus on an object, then use live view to do the same and see if the images are as sharp as each other.
I tried with auto focus at f1.8 but my lens was focusing on the background (causing severe blur on the subject. I couldn't figure out how to foreground focus on auto. Would this be down to being too close to the subject (the can)?
 
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#23
That sounds like good advice! As I look at that photo more, I can already see subtle things like the back of the table being swallowed up by the bokeh so hopefully I can get the hang of finding out where I need it to be fairly quick.

Will definitely get back out in the garden tomorrow to shoot a few DoF try outs.
Yes, practise is your friend, move forwards and backwards, DOF is a lot of things but to start it’s about distance to subject and subject to back ground distance.

Also look up DOF explained and focus plane, these will get you started and set you up to test different distances and such.
 
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#24
You can't let the camera choose where to focus at f1.8 (or ever really, unless you know in detail the auto focus modes of your camera e.g face detect) , you need to manually pick a focus point which is on the can if you want it to be in focus.

If the camera is focusing on the background you are either a) letting the camera pick the focus point, b) using the wrong focus point or c) using a lens which is struggling for whatever reason (low quality/within the minimum focus distance etc)
 
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#28
I tried with auto focus at f1.8 but my lens was focusing on the background (causing severe blur on the subject. I couldn't figure out how to foreground focus on auto. Would this be down to being too close to the subject (the can)?
Are you taking control of which single AF point you are using to take the photograph? Didn't you previously mention using the single central point?

If you are taking control I cannot understand why you say it AF's on the background but you can manually focus on the foreground subject.

Here is the Nikon online manual page that deals with focus settings
https://onlinemanual.nikonimglib.com/d3500/en/09_more_on_photography_05.html#af-area_mode

NB the full manual is there for you.
 
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#29
I tried with auto focus at f1.8 but my lens was focusing on the background (causing severe blur on the subject. I couldn't figure out how to foreground focus on auto. Would this be down to being too close to the subject (the can)?

Your problem is that you have it on Auto, you need to be taking some kind of control of the camera and setting the focus points yourself.
 
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#30
I think there's been some breakdown of communication in this thread.

Just to confirm, I shoot in full manual mode and also focus manually.

I was just testing the auto focus (as a one off) based on the reply that stated:

"Manual focus isn’t very reliable, especially at shallow DoF."

I will take a look in the manual to see if I can set multiple focus points.

Thanks all
 
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#31
I think there's been some breakdown of communication in this thread.

Just to confirm, I shoot in full manual mode and also focus manually.

I was just testing the auto focus (as a one off) based on the reply that stated:

"Manual focus isn’t very reliable, especially at shallow DoF."

I will take a look in the manual to see if I can set multiple focus points.

Thanks all
Not sure why you'd focus manually (unless shooting macro) as modern cameras aren't designed for it as they don't have focus screens that help you get it right, and certainly the kit lens isn't very good for it either as the MF isn't very smooth or accurate.

Each to their own but given your camera is almost certainly better at focussing than you, if you know how to use it, why not do that?
 
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#32
Yep that's your issues, you should be using single point auto focus in 99% of situations. You mentioned you'll check your manual to find multiple focus points - this is not what you want (see my post above).

Manual focus without using a tripod at very shallow dof is asking for trouble!

Manual focus is very useful when you have full control over the shot i.e. A landscape shot on a tripod, or if you're using range focusing to pre-determine your depth of field and focus area. Otherwise auto is the way to go (with single point). :)
 
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#33
And as a suggestion, rather than full manual, you would be well served using "P" mode which allows you to override either shutter or aperture, but will compensate automatically to achieve correct exposure. Likewise, you should be able to override the exposure by n stops, which you can use where you know your subject is not going to be exposed correctly. For example, on a bright day, taking a photo of something in shadow you can either use spot metering (best) or overexpose the auto setting. Either option will result in blowing out highlights, but dynamic range is limited and you should use it on your subject.


As @Nawty says, DSLR screens are crap for getting focus right, especially mirrorless, although they can compensate by providing a display magnifier. My personal habit (on micro four thirds Olympus) is to use S-AF+MF for most instances which will auto focus and then allows you to tweak the focus if needed, in combination with "edge detect" (an Olympus digital attempt at providing a split prism effect) that can help.
 
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#35
I think there's been some breakdown of communication in this thread.

Just to confirm, I shoot in full manual mode and also focus manually.

I was just testing the auto focus (as a one off) based on the reply that stated:

"Manual focus isn’t very reliable, especially at shallow DoF."

I will take a look in the manual to see if I can set multiple focus points.

Thanks all
Ah! miscommunications ~ not to worry.

However, in your post #5 you talk of "single focus point" to me and possibly all of us this means an AF point.

When using Manual Focus (MF) none of the AF are used, you are judging focus of whatever the subject is on the Matte (surface) Focusing Screen. As pointed out by others on modern AF digital as there is no (old style) split prism for 'focusing' it is hard to be sure on critical sharpness of focusing (when/where required depending subject).

On this page in the manual I linked to it deals with MF and mentions that some lenses AF-P designated give some form of focus confirmation. https://onlinemanual.nikonimglib.com/d3500/en/09_more_on_photography_05.html#manual_focus
This online manual is quick to use and easy to search even on my smartphone.....and cannot say that about all such online resources!

PS just why are you using MF? I have been using AF from film days back in 1987 because I was missing too many shots due my none too quick MF ability. My last MF SLR was a Pentax P30 and first AF one was Canon 650
 
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#36
Brill, very helpful. I think it's me confusing things not knowing the lingo yet!

I could be wrong (without checking) I'm sure in my settings I have AF-S set,

However, from here, on my lens:

Clicking M/AF made my example photo focus on the background - I'm certain I was unable to set a focal point through the viewfinder.

Clicking M enabled me to turn the front of then lens to focus on the foreground (or the subject in this case).
 
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#37
Brill, very helpful. I think it's me confusing things not knowing the lingo yet!

I'm certain I was unable to set a focal point through the viewfinder.
Then, you were not using the right focus points or method.

One thing worth noting, you started off by saying that the original photo was about half body length, suggesting that it was about - 3? - meters away.

The extremely shallow depth of field that you get from a 50mm/1.8 of 2cm or so is really only for about 1 meter away, by the time you get to 3 meters the maths says you should get something like 20cm, meaning you should not be noticing a small amount of sway, the fact that you can see an issue with the focus means (not to harp on about it, but hey ;) ) that your MF attempt is wrong (for the reasons said).

If you are using a 50mm lens at distances of 3m or over, you can easily use AF with a centre focus spot. Point the centre at your subject, depress the shutter half way to lock the focus and exposure, then reframe to the way you want before taking the image.

ETA: What do I know? more like 40cm than 20cm - here's a useful calculator https://www.photopills.com/calculators/dof
 
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#38
Brill, very helpful. I think it's me confusing things not knowing the lingo yet!

I could be wrong (without checking) I'm sure in my settings I have AF-S set,

However, from here, on my lens:

Clicking M/AF made my example photo focus on the background - I'm certain I was unable to set a focal point through the viewfinder.

Clicking M enabled me to turn the front of then lens to focus on the foreground (or the subject in this case).
Can I suggest you (re)read the page link I posted in post #28 plus whilst there, if you have not done so already, read through the whole manual. Just knowing what all of the D3500 controls & settings do will answer a lot of your questions.........then more will crop up that the manual may not answer>>>>TP here for you when needed.
 
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#39
Brill, very helpful. I think it's me confusing things not knowing the lingo yet!

I could be wrong (without checking) I'm sure in my settings I have AF-S set,

However, from here, on my lens:

Clicking M/AF made my example photo focus on the background - I'm certain I was unable to set a focal point through the viewfinder.

Clicking M enabled me to turn the front of the lens to focus on the foreground (or the subject in this case).
hi mate, i could be completely wrong here, but i believe AF_S stands for autofocus single, which means the camera will focus once and hold that focus until you re-press the shutter/focus again, the other option would be AF_C (autofocus continues) which means as you hold the focus button the camera will constantly adjust focus as you move or your subject moves.

The above is not to be confused (most ppl do) with focus point/points, your body will have multiple focus systems from single point AF and some others, maybe 3d tracking or some variation etc.

Most of the post above are talking about your AF point and not the AF-S, you should be using single point focus (basically you will get a single red square in your viewfinder.
 
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