Object focus

Chunky Monkey

Sorry this is going to sound like an ignorant question to all you professional photographers and I might get a couple of RTFMs but...

How do you focus on the object in the foreground and make the background out of focus (using an SLR)?

Rojo

Use a large lens aperture opening, ie something like 1.8, 2.8, etc. :-)


The distance between the object in focus also has an effect. The closer you are to the object, the more out of focus the background will be!

stcstc

do a search on google for depth of field, this will explain how it works, there are lots of variables so if you read a webpage explanation rather than a log winded post here

Chunky Monkey

I got the Nikon D40. On the box it says f/3.5-5.6. Is that the aperture range?

I think I had it set on auto...

Chunky Monkey

Thanks guys

ThOnda

I hope I won't be wrong, but most of us have set the Av program - Aperture priority. It is the most powerful creative setting you can use from early beginnings of using camera.
And you are shooting for free, just try what you can do with it. Minimum and maximum aperture, focused at something close and far in the distance...

It's a toy, so enjoy!

sineadw

The F 3.5 refers to the maximum aperture when you're not zooming at all, the 5.6 is when you're at full zoom. (the smaller the number the bigger the aperture - confused the hell out of me at the start :rolleyes: ) Basically, the smaller the number the more out of focus the background will be. Although as someone already said it depends how far away you are. Yeppers - play around with the AV mode. Get in close and far away and mess about with the smaller aertures too and you'll get the hang of it

Fajitas!

AV mode is A on Nikons...

isadub

Have a look at this post (esp the pic of the fly about 1/2 down)...It'll explain DOF.

As to how to focus on an object: if you look through your viewfinder, you should see several black marks "[]" (focus points) superimposed on the image. If your camera is set to auto, it'll probably take an average or focus on whatever's moving. If you set your camera to Aperature-priority, you can choose which of the focus points the camera will focus on. Looking at your photo, you could move the focus point left to focus on the tree or move it to the centre or to the right to focus on the flowers in the foreground.

As to how to get the background blurry, that'll cost you money in expensive lenses like f1.8 etc (see link above). You should get familiar with your camera before you start spending loadsa money on lenses.

Stokolan

isadub wrote: »

Have a look at this post (esp the pic of the fly about 1/2 down)...It'll explain DOF.

Thats a great article. Just read thru it and it cleared up a fair bit for me..

AnCatDubh

Not sure if others will agree but the lower the aperture value (f5.6, f3.5, f2.8, f1.7) the narrower the 'depth of field' or amount of the image that will actually be in focus and personally speaking (again not sure if others will agree), i think it becomes more difficult to get the focus 'just right'. Perfectly do-able with practice and very rewarding when you can create on demand - but very frustrating when you get too much of that 'lovely blur' and not enough in focus (eh.... a ruined shot). Again practice should sort that out for you.

Although as a previous poster has said, lens with low (numerically) aperture values can be expensive, you can get some great lens that are in the 'prime' category and have a low aperture value (f2.8, f1.7, f1.4) at reasonable costs - the primes are fixed focal lengths hence won't allow you to zoom. But they have the added advantage of being far more superior in low light conditions than lens with higher aperture values (eg. f5.6) - it is also the case that generally the quality of the glass (or expensive plastic?) in primes are superior to that of zoom lenses.

Hope that helps.

ThOnda

I'll try to make me think about the second question.

Prime - a lens designed for one focal length - no need for movable parts (rails joints lens housings), no need for empty space, one angle captured by the lens = simple lens without parts reducing it's value and mostly internal diameter (what is aperture).

Zoom lens - calculated for few focal lengths, more complicated, lot's of "non-optical" parts in lense housing = less space for plastic (or glass). That fives you smaller hole (bigger aperture).

Chunky Monkey

Thanks Isa that article is great. I don't intend to spend loads of money on other lenses just yet. My dad gave me his old Olympus OM-20 film camera today. He has a 70-200mm Tora zoom lens with it. Alas it doesn't fit on my new toy but I'll get it fixed and learn to use that one too

Thanks to the others too, I'm starting to scrape away the tip of the iceberg and get some understanding of it, but I never realised there was so much before!

isadub

Good luck with the photography.

Your sig says you're based in Ballymun. I'm just down the road in Glasnevin so maybe our paths will cross someday. Having said that, I'm not going to tap someone on the shoulder in the Botanic Gardens and ask 'are you the Chunky Monkey'!!:D

challengemaster

Chunky Monkey wrote: »

I don't intend to spend loads of money on other lenses just yet.

you may say that all you like, I said it too when I started 3~ months ago.. I now have a L series lens which cost ~900€..amongst other lenses, battery grip, camera bag, etc etc.. becoming a gear junkie is quite easy!

Fajitas!

isadub wrote: »

Good luck with the photography.

Your sig says you're based in Ballymun. I'm just down the road in Glasnevin so maybe our paths will cross someday. Having said that, I'm not going to tap someone on the shoulder in the Botanic Gardens and ask 'are you the Chunky Monkey'!!:D

I'm across the road in Drumcondra.

All the more reason to have a Botanics meet.

Challengemaster, whatever Freudian theories you put into it, I think it's mostly a male want for more (and bigger) lenses

challengemaster

Fajitas! wrote: »

Challengemaster, whatever Freudian theories you put into it, I think it's mostly a male want for more (and bigger) lenses

So Al, you're telling me that you want other guys big lenses?

Fajitas!

I'd rather my own tbh. Though you were telling me for a long time that you wanted my 24-70L... Whatever that says about you...

Now. Back on topic lad.

challengemaster

Fajitas! wrote: »

I'd rather my own tbh. Though you were telling me for a long time that you wanted my 24-70L... Whatever that says about you...

Now. Back on topic lad.

pff, i got my own now! I dont need yours!

I'd ehm, post a pic with 2.8 aperture to show an example of object focus if i still had lightroom.. bleh >_>

whyulittle

Fajitas! wrote: »

I'd rather my own tbh. Though you were telling me for a long time that you wanted my 24-70L... Whatever that says about you...

Now. Back on topic lad.

Along with TelePaul and RCNPhotos talking about sending each other shirtless pics over on the 2007 meet ups thread, this place is getting weirder by the day! :eek::eek::D

brav

isadub wrote: »

Have a look at this post (esp the pic of the fly about 1/2 down)...It'll explain DOF.

Thats a good read, explained it nicely

ThOnda

Do you know what we (men) compensate, when we buy BIG lenses?

Shaky hands

challengemaster

ThOnda wrote: »

Do you know what we (men) compensate, when we buy BIG lenses?

Shaky hands

Ah, but the question is what caused the awful shakeyness