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Thread: type of lens, focal length and more..

  1. #1

    Default type of lens, focal length and more..

    with regards to the other thread on "portraiture" and focal length, i would like to clarify why it would matter.

    let's just say you were @ 24mm, standing close to the subject.

    VS

    @ 200mm, standing further from the subject but zooming in to get the same perspective.

    will the 200mm still make the subject look more flattering?


    another thing is about aperture values. i know a large aperture will give shallow DOF and vice versa.

    Let's say i'm doing a product shot of a clothing on a hanger, against a wall. does it matter if i use f1.8 or f32?

    another scenario i want to clarify is a controlled shot ( with tripod and lightings ) of a half body against a plain background, about 1.5m away from the subject. does it matter if i use f1.8 or f32?

    in these two cases, we assume everything is at optimal values ( sufficient shutter speed/iso to prevent blurring ). any difference between the 2 aperture values?

    lastly, a question on lenses. what are the differences between a 3rd party lens (say tamron ) vs original manufacturer ( say canon ) lens, assuming same specs? i'm using a 450d - would it be wiser to purchase a 2nd hand tamron or canon lens?

    Thanks for reading!

  2. #2

    Default Re: type of lens, focal length and more..

    when you use a 200mm lens, the PERSPECTIVE is different, it isn't as simple as taking a crop from the middle of 24mm lens.

    other than that, with longer focal lengths, for same aperture setting you get shallower depth of field. a 200mm lens, as long as your subject is far away from background, backgorund will be thrown out of focus and into bokeh. for a 24mm lens, that is next to impossible unless you happen to be standing in the middle of sahara desert or something.

    if you are doing a product shot of a clothing hanging on wall, the subject-background distance is minimal, it does not really matter what aperture you use when it comes to depth of field. HOWEVER, most lenses are not sharpest when wide open (for aperture), so you might want to stop down a little, to perhaps f/2.8 or f/3.5 for optimal results.

    lastly, the main difference most people will tell you is Quality Control, but frankly, if you check the lens when buying and you are happy with it, who cares.

  3. #3
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    Default Re: type of lens, focal length and more..

    with regards to the other thread on "portraiture" and focal length, i would like to clarify why it would matter.

    let's just say you were @ 24mm, standing close to the subject.

    VS

    @ 200mm, standing further from the subject but zooming in to get the same perspective.

    will the 200mm still make the subject look more flattering?

    -> For head shots, Yes. For full length portraiture, Probably No. The important thing is to work out your min and max working distance. Min working distance to make your subject look flattering and Max working distance for the sake of practicality. I tried a half body shot using a 135mm on a crop sensor and at that distance you see people moving into your frame and you have to raise your voice at your model to be heard outdoors, definitely not very practical. Once you work out your working distance, choose a focal length that fits whatever part of the subject you need in the frame.

    another thing is about aperture values. i know a large aperture will give shallow DOF and vice versa.

    Let's say i'm doing a product shot of a clothing on a hanger, against a wall. does it matter if i use f1.8 or f32?

    -> I would use something like f/4 to f/8 because most lens are not at their sharpest wide open and when the aperture gets too small, diffraction causes you to lose sharpness.

    another scenario i want to clarify is a controlled shot ( with tripod and lightings ) of a half body against a plain background, about 1.5m away from the subject. does it matter if i use f1.8 or f32?

    -> See above. However in this case some might choose a shallow DoF (i.e. f/1.8) and focus on the eyes while the hair and ears become slightly out of focus, but I see this as an artistic choice. Also, with enough lighting you can do fun things with the background but thats another topic...

    in these two cases, we assume everything is at optimal values ( sufficient shutter speed/iso to prevent blurring ). any difference between the 2 aperture values?

    lastly, a question on lenses. what are the differences between a 3rd party lens (say tamron ) vs original manufacturer ( say canon ) lens, assuming same specs? i'm using a 450d - would it be wiser to purchase a 2nd hand tamron or canon lens?

    -> http://www.photozone.de/

    Thanks for reading!
    Last edited by kaixiang; 18th March 2009 at 09:38 AM.

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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by night86mare View Post
    when you use a 200mm lens, the PERSPECTIVE is different, it isn't as simple as taking a crop from the middle of 24mm lens.
    Perspective depends on subject distance and NOT focal length. If you stand just as far and have unlimited resolution and crop you get the exact same thing when you crop. I used to have the same misconception.

    I hope this helps:
    http://www.earthboundlight.com/photo...al-length.html

  5. #5

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by kaixiang View Post
    Perspective depends on subject distance and NOT focal length. If you stand just as far and have unlimited resolution and crop you get the exact same thing when you crop. I used to have the same misconception.
    what i meant was resolution and other factors, like camera shake for longer focal lengths

    anyways, i see why my answer seemed weird, i did not read the ts' question properly.

    thanks for clarification.

  6. #6

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    with regards to the other thread on "portraiture" and focal length, i would like to clarify why it would matter.

    let's just say you were @ 24mm, standing close to the subject.

    VS

    @ 200mm, standing further from the subject but zooming in to get the same perspective.

    will the 200mm still make the subject look more flattering?

    the longer focal length will give a more flattering appearance for portraiture. if you shoot both pictures with a similar fov, the 24mm will give a somewhat distorted appearance. the 200mm will allow better subject-background isolation and a slight "3D" feel to the photo.


    Quote Originally Posted by tester99 View Post
    another thing is about aperture values. i know a large aperture will give shallow DOF and vice versa.

    Let's say i'm doing a product shot of a clothing on a hanger, against a wall. does it matter if i use f1.8 or f32?

    another scenario i want to clarify is a controlled shot ( with tripod and lightings ) of a half body against a plain background, about 1.5m away from the subject. does it matter if i use f1.8 or f32?

    in these two cases, we assume everything is at optimal values ( sufficient shutter speed/iso to prevent blurring ). any difference between the 2 aperture values?
    the f/stop will make a difference to how much of the clothes is in focus. use a dof calculator if you are not sure. your camera probably will not allow u to stop to f/32 anyway. again, with the controlled shot, assuming you know how to control the other parameters, its just a matter of how much u want to be in focus. again, reading up on dof will help u.

    Quote Originally Posted by tester99 View Post
    lastly, a question on lenses. what are the differences between a 3rd party lens (say tamron ) vs original manufacturer ( say canon ) lens, assuming same specs? i'm using a 450d - would it be wiser to purchase a 2nd hand tamron or canon lens?

    Thanks for reading!

    depends on your budget and your tolerance to 3rd party gear. i won't pick 3rd party unless canon doesnt have what i want.

  7. #7

    Default Re: type of lens, focal length and more..

    thanks for all the replies!

    from the above i conclude some things:

    zoom to the max ( but within working distance ) while taking portraits.

    flipfreak : like what the other poster has mentioned, there isn't any subject-background distance. so the f stop still matters?
    another thing - since you said 200mm will give a slight 3d feel, does it apply to the product shot too? should i do a max zoom when taking pictures of the clothes?

    hmm, is 3rd party really that bad? those brands are quite reputable isn't it?

    what's the reason for lens not being at their sharpest when wide open? a pretty big concern because i'm often in A mode with largest setting.

    another question - cameras are least stable @ max zoom and most stable @ min. zoom. is this statement true?

  8. #8

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    thanks for all the replies!

    from the above i conclude some things:

    zoom to the max ( but within working distance ) while taking portraits.

    flipfreak : like what the other poster has mentioned, there isn't any subject-background distance. so the f stop still matters?
    another thing - since you said 200mm will give a slight 3d feel, does it apply to the product shot too? should i do a max zoom when taking pictures of the clothes?

    hmm, is 3rd party really that bad? those brands are quite reputable isn't it?

    what's the reason for lens not being at their sharpest when wide open? a pretty big concern because i'm often in A mode with largest setting.

    another question - cameras are least stable @ max zoom and most stable @ min. zoom. is this statement true?
    it does to a certain extent. look macro lenses. the shooters usually stop down quite alot in those instances. usually u looking at f/8 or more for product shoots. no one shoots wide open in those instances. as i mentioned, use a dof calculator to figure out the optimum dof for the shoot. u need to consider the focal length, the camera-subject-background distance, the f/stop, the sensor size. don't need to zoom to 200mm la. not practical also.

    lens are usually not sharpest wide open cos of how its designed. u do get lenses sharp wide open but depends on what kind of lens it is. most of the L primes are sharp wide open.

    focal length are more susceptible to camera shake at longer focal lengths. but i am assuming u are going to use a tripod for the shoot.

  9. #9

    Default Re: type of lens, focal length and more..

    alright, thanks for the answer.

    what about compacts with M mode? are they sharp wide open? ( usually f2.8 )

    if it's a controlled shot, zoom @ 200mm doesn't matter also ma. it'll be on tripod anyway like you say.

    edit : have an irrelevant question here : why is there no "portraiture" section in CS? everything except portraits are missing in the forum..
    Last edited by tester99; 18th March 2009 at 06:36 PM.

  10. #10
    Moderator catchlights's Avatar
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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    ...............
    edit : have an irrelevant question here : why is there no "portraiture" section in CS? everything except portraits are missing in the forum..
    you sure?? very sure??

    than what is Portraits and Poses to you?
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  11. #11
    Moderator catchlights's Avatar
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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    ..............................

    another question - cameras are least stable @ max zoom and most stable @ min. zoom. is this statement true?
    Quote Originally Posted by tester99 View Post
    .........................
    if it's a controlled shot, zoom @ 200mm doesn't matter also ma. it'll be on tripod anyway like you say. .................
    FF has already replied you.
    and it also subject to how sturdy is your tripod, plus some other factors.
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    Moderator catchlights's Avatar
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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    with regards to the other thread on "portraiture" and focal length, i would like to clarify why it would matter.

    let's just say you were @ 24mm, standing close to the subject. ............
    if you have no apparent artistic reason for doing so, it only shows you don't like this person very much.
    Shoot to Live, Live to Shoot
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    Moderator catchlights's Avatar
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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    ............................

    Let's say i'm doing a product shot of a clothing on a hanger, against a wall. does it matter if i use f1.8 or f32?
    f1.8, picture not very sharp, soft at corner.

    f32, picture also not very sharp, deflection kicks in.

    Use f8~f11

    Quote Originally Posted by tester99 View Post
    another scenario i want to clarify is a controlled shot ( with tripod and lightings ) of a half body against a plain background, about 1.5m away from the subject. does it matter if i use f1.8 or f32? ...............................
    see above.
    Shoot to Live, Live to Shoot
    www.benjaminloo.com | iStock portfolio

  14. #14

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by tester99 View Post
    alright, thanks for the answer.

    what about compacts with M mode? are they sharp wide open? ( usually f2.8 )

    if it's a controlled shot, zoom @ 200mm doesn't matter also ma. it'll be on tripod anyway like you say.

    edit : have an irrelevant question here : why is there no "portraiture" section in CS? everything except portraits are missing in the forum..
    like i mentioned, the dof in the photo also depends on sensor size. a compact has a tiny sensor. as a result, a f/2.8 lens will give u maybe f/8 or so dof on a 35mm sensor. great if you shooting things that needs that kind of dof. you also don't have to worry abt soft corners, etc etc. which is the selling point of a 4/3 system. but compacts usually don't have good lenses though.

    200mm also depends on how close your lens can focus.

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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by catchlights View Post
    if you have no apparent artistic reason for doing so, it only shows you don't like this person very much.
    LOL. By the way different lens are sharp at different apertures, what I can remember is that the Nikon 18-55 kit lens is sharpest at f/8 to f/11 but I'm quite sure the 50 f/1.8 is sharpest around f/4 to f/8, but I do agree that most lens perform really well at f/8 except some very special lens designed to be used wide open.

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    Default Re: type of lens, focal length and more..

    To supplement what flipfreak said:

    http://www.dofmaster.com/dofjs.html

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    Default Re: type of lens, focal length and more..

    Quote Originally Posted by kaixiang View Post
    Perspective depends on subject distance and NOT focal length. If you stand just as far and have unlimited resolution and crop you get the exact same thing when you crop. I used to have the same misconception.

    I hope this helps:
    http://www.earthboundlight.com/photo...al-length.html
    perspective depends on focal length too. try shooting a model with a 50mm lens, vs a 100mm lens outdoors and you'll see the difference.
    eat. drink. shoot

  18. #18

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by catchlights View Post
    you sure?? very sure??

    than what is Portraits and Poses to you?
    yeah very sure. i know the reason why i couldn't see it in the first place. ONLY portraits and poses section is cloaked when you're not logged in. that's why i didn't see that section..

  19. #19

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by catchlights View Post
    if you have no apparent artistic reason for doing so, it only shows you don't like this person very much.
    well.. no harm trying new perspectives/angles or whatnots, right?

  20. #20

    Default Re: type of lens, focal length and more..

    Quote Originally Posted by kaixiang View Post
    To supplement what flipfreak said:

    http://www.dofmaster.com/dofjs.html
    ahh..dof calculator.. numbers and more numbers..

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