Auto and manual focus query

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Abhi_UK

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Hi,
Could anyone please clear my understanding regarding Auto and manual focus?

I'm new to DSLR and planning to buy my 1st one. Yester day I was in a shop trying out some DSLRs. I took a Nikon D5100 with 18-55mm lens on it. I zoomed it to 55mm and turned on the manual focus switch on the lens. I focused a man standing in front of me. In the view finder the man is clearly visible and the background became little bit blur. Now I suppose I’ve done all focusing manually and ready to shoot. (I could not take any pic as there was no memory card installed)My question is if I press the shutter half way down does the camera focus again?? Is it called autofocus done by the focus motor in lens or camera?? If it is not, then where the autofocus came into picture in this whole process?:thinking:

Also what happen if press the shutter instantly without pressing half way down.

The questions might appear stupid :bonk:but this will help me to understand the use of a built in focus motor in the lens.
 
if you turn the switch on the lens to manual focus then pressing half way will do nothing to the focus. depending on the setup it will do other things, like exposure calculation
 
joescrivens said:
if you turn the switch on the lens to manual focus then pressing half way will do nothing to the focus. depending on the setup it will do other things, like exposure calculation
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Thanks,
If again i switch on the auto focus then waht will happen?? will the camera again focus on the subject eleminating the focus that i've set manually on the subject?
 
If the lens is set to manual focus and you press the shutter all the way down quickly it will just take the shot with the settings you have used for exposure.
 
Abhi_UK said:
Thanks,
If again i switch on the auto focus then waht will happen?? will the camera again focus on the subject eleminating the focus that i've set manually on the subject?
Click to expand...

If you switch the lens back to auto and press down on the shutter release button it will focus automatically. If you set the focus point to the object you were already focused on then the autofocus probably wont move much if at all.
 
Agreed, if you have focused manually on something, then switch back to AF and the camera starts to auto focus when you half press the shutter button, it will probably only make a couple of minor adjustments and immediately lock the focus.

If you have lenses with FTM (full time manual) focussing and a camera body with a dedicated auto focus button then you can just leave the AF on all the time and only use it when you want.
 
Thanks a lot for the info.
Hmm...that means I can use a non AF-S (like Nikkor 50mm f1.8 D AF) in D5100. The guy from the shop was telling me it will not fit at all with D5100. But actually it will not autofocus with D5100. But if I set the focus manually I can take good pics. What's your suggestion on this? Will it be a valid combination for taking good portrait pics? (This lens is irresistible as it’s having aperture F1.8 and price is approx £ 100 only. But only thing is bothering me is that it is not a AF-S)
 
I am using a D5000 and I use old manual focus lenses from time to time, I have a nikkor 50mm 1.8 and an 28mm f.28 manual focus lenses which I use. I would suppose that a D5100 would have the same compatibility. Here is an interesting link about lens compatibility for manual focus and auto focus with Nikon range LINK
 
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Manual focus is fine for portraits. It helps a lot when your subject is not moving.
 
Excellent!!!
I was going through the link. For some of the lenses it is written as "No Meter" if i use it with D5100. What does it mean?
 
Abhi_UK said:
Excellent!!!
I was going through the link. For some of the lenses it is written as "No Meter" if i use it with D5100. What does it mean?
Click to expand...

It means the cameras internal exposure meter will not work with that lens so you will have to either guess it or use a external light meter. It isn't a problem with digital really as you can use take test shots and delete them when needed to determine correct-ish exposure as results are instant. Originality does not arrive without experimentation ;)
 
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sc0ttie said:
It means the cameras internal exposure meter will not work with that lens so you will have to either guess it or use a external light meter. It isn't a problem with digital really as you can use take test shots and delete them when needed to determine correct-ish exposure as results are instant. Originality does not arrive without experimentation ;)
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Cool!!:thumbs: Thank you.
 
Now I’m convinced to go for Nikon D5100 over Canon 600D. Not having a built in focus motor will not scare me now.
 
Have you tested the Canon yet? I don't want to comment too much on the whole Nikon vs Canon thing, since I'm a pure Canon user and I have access to a LOT of kit all of which is Canon, however the D5100 does look like it has a pretty good spec.

Personally I wouldn't bother with the 600D, it's basically the same as the 550D with a stupid flip out screen (proper photographers won't use live view anyway) and some other very minor differences.

Having the AF motor in the lens rather than body helps a lot, because then are no incompatibilities with lenses (any lens that works on a 5Dmk2 will work on a 550D with full AF, metering etc).

For a beginner I would say AF and AE are quite a valuable thing.
 
Coming from a 5D Mk1 (and a lot of film cameras that get fairly regular use) with no live view, I have to say that it's occasionally dead handy on my Panasonic G2, especially with the twist and flip screen.

The screen happens to be just about the same size as a 645 medium format viewfinder when used with a waist level finder...
 
Musicman said:
Coming from a 5D Mk1 (and a lot of film cameras that get fairly regular use) with no live view, I have to say that it's occasionally dead handy on my Panasonic G2, especially with the twist and flip screen.

The screen happens to be just about the same size as a 645 medium format viewfinder when used with a waist level finder...
Click to expand...

Hate to tell you this, but you're not a proper photographer then :cuckoo:
 
ohara said:
Have you tested the Canon yet? I don't want to comment too much on the whole Nikon vs Canon thing, since I'm a pure Canon user and I have access to a LOT of kit all of which is Canon, however the D5100 does look like it has a pretty good spec.

Personally I wouldn't bother with the 600D, it's basically the same as the 550D with a stupid flip out screen (proper photographers won't use live view anyway) and some other very minor differences.

Having the AF motor in the lens rather than body helps a lot, because then are no incompatibilities with lenses (any lens that works on a 5Dmk2 will work on a 550D with full AF, metering etc).

For a beginner I would say AF and AE are quite a valuable thing.
Click to expand...

What is it that live view does that makes a potentially 'proper' photographer become improper when they use it? :lol:
 
Hi Abhi. I bought a D5100 as my first dslr back in july, love it so far. But i do use autofocus most of the time. I know the afs lenses are more expensive but they are all i intend to buy in the future.
 
ohara said:
Have you tested the Canon yet? I don't want to comment too much on the whole Nikon vs Canon thing, since I'm a pure Canon user and I have access to a LOT of kit all of which is Canon, however the D5100 does look like it has a pretty good spec.

Personally I wouldn't bother with the 600D, it's basically the same as the 550D with a stupid flip out screen (proper photographers won't use live view anyway) and some other very minor differences.

Having the AF motor in the lens rather than body helps a lot, because then are no incompatibilities with lenses (any lens that works on a 5Dmk2 will work on a 550D with full AF, metering etc).

For a beginner I would say AF and AE are quite a valuable thing.
Click to expand...

Thanks ohara
I did have lot of confusion regarding Canon (550/600D) vs Nikon (D5100). Both are very good cameras…no doubt. But I’m going for Nikon for only one reason …its better performance in low light because of its low noise in high ISO. Low light photography is one of my crucial requirements. (my current camera Canon SX 30 is not up to the mark)
Yes I’ve tested both the cameras in shop (though I could not take any pics as there was no memory card installed). In my initial observation I found the below things
1. Canon has better looks
2. Canon has better design – better button placement, more dedicated buttons and better grip
3. Nikon lenses little bit smoother than canon (specially the 70-300mm…canon one is very hard to rotate for zoom. Although I felt Sony is the best in this category)

Other than this I found no differences. As far as the performance concern I’m relying on review articles and videos.
Regarding the flip out screen..that is not in my priority list either. Had there been a Nikon model similar to D5100 without flip out screen (like Canon has 550D) I’d have considered that. Then I’d have more money to invest on lens.
As far as the focus motor concern, yes that is the only big disadvantage with D5100. But Nikon has plenty of lenses with focus motor which perfectly matching my requirement. Only thing the price is little bit high.

And also there is no issue with AE for D5100 I guess (or is there? not sure). It's only the AF motor it doesn't have.
 
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phil_b said:
Hi Abhi. I bought a D5100 as my first dslr back in july, love it so far. But i do use autofocus most of the time. I know the afs lenses are more expensive but they are all i intend to buy in the future.
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Hi Phil,
Thanks for the info. I’m also considering AF-S lens only. But I stuck only on 50mm D f1.8 AF Prime.If I go for the AF-S version (50mm F1.8 G AF-S ….though I don’t know what’s the difference between D and G) I’ve to pay almost double the amount.:bang:
Other than this I’m planning to buy 55-300mm f4.5-5.6 AF-S VR ED and obviously the 18-55mm kit to cover the wide angle.
Do you think it will be good combination if I go for the 50mm prime without focus motor.:help:

Also as u already have D5100, just wanted to check how is its performance in low light. Are u happy with the overall performance?
One more thing I’ve heard that it is possible to configure “fn/Self timer” button in front (just below the flash button) to a dedicated button to control any one in-built function like ISO, white balance etc. Is it true?
 
50mm F1.8 G AF-S is a new design , it is a much better lens compare to the old d version. Have you consider the 35mm F1.8 ? It is cheaper then 50mm afs and it is 52mm Full fame equivalent therefore more useful.
 
hyeongsoong said:
50mm F1.8 G AF-S is a new design , it is a much better lens compare to the old d version. Have you consider the 35mm F1.8 ? It is cheaper then 50mm afs and it is 52mm Full fame equivalent therefore more useful.
Click to expand...

Thanks,

Yes i can consider 35mm. But will it be good for protrait? I mean I'll be using this mostly for close up protrait photography. Then which one will be good 50mm or 35mm.
 
35mm won't be the best lens for portrait. If it's on a crop then it effectively goes to 50mm which is ok, but the 50mm would be better as a portrait lens for head and shoulders type stuff - it would become effectively 75mm which is more perfect for close up portrait
 
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