There is a lot of argument on this but mostly boils down to distance rather than focal length. Longer focal length just makes you stand further to fill in the same frame as the wider lens.

There has been experiment done on this before. If you use wide and long focal at exact same spot and distance shooting same subject, you will notice that background "compression" are the same on both. Difference is you have to crop in on the wider shot to get the same field of view as the longer focal, thus result in less sharp image and also less bokeh.

Exactly..

I understand where you are coming from but it's actually not appropriate to compare at "same spot".

The difference between 24mm and 90mm for example is the field of view.

When you compare it at the same FOV - it will be the same.

The thing is you can't compare base on spot, you have to go with the whole frame - that's why 24mm and 90mm will be different because the light falls in differently. Same face occupying same area on the frame, 24mm you won't see the ears while 90mm you can. In order for 24mm to get the same effect you have to stand far back until the face falls within the 90mm field of view.

Not sure but i think u got the 24 and 90 backward at last sentence.

FOV is not exactly the same between focal length and hard to explain. Yes you can get same FOV on "subject" if you move closer with wider lens. But the "background" will still be wider than the longer focal despite having same subject at same size. Also the face be little bit more distorted for wider lens cause you have to get closer. There are a lot relations at work here but one thing that is consistent is the distance from the camera to the subject in relation to background.

No, I didn't mix up. I shoot portrait at 22mm before.

That's why people use longer focal length to shoot portrait. Longer focal length so you have to stand further too but you get the face and even the ears.

When on wider focal length, the way light falls to the lens you get less ears.

more prefer is use 50mm for you can general use.

Thats why i ask why u said have to stand further back with 24mm to get same fov as 90mm? Suppose to be other way around. Unless u talking about the distortion but 24mm on apsc wont be distorted enough to wrap out the ears.

This post has been edited by DaddyO: Dec 22 2016, 04:04 PM

Confirm sure what I am trying to convey is as what I wrote.

You're just not understanding what I'm trying to say.

IF you are using 90mm and you want to achieve same subject size - you move backwards. That's what you're saying.

I'm on the other hand saying that if you are on 24mm and you want the subject to reach the 90mm's FOV, you have to go backwards. By then the face will occupy a much smaller area of the frame.

Errrr.....still dont understand. Lets just agree to disagree.

I think I understand what "goldfries" trying to explained. As i am using 25mm to shoot portrait right now.
Perhaps the so called FOV you are trying to say is not just field of view, but also the area which is "in focus"?
Or can i say it is actually the DOF?
My definition, FOV and DOF is different.
FOV: The widest dimension you can see from a frame, including all out focus and in focus subject which can be seen in the whole frame.
DOF: The FOV which is "In Focus" only.

Based on my experience, using a 25mm lens shooting portrait, as i move closer to the face to reach the 85mm FOV, the DOF is much much shorter than the DOF
which is shoot with a 85mm lens when compare side by side. Most of the time, i have to slow down a step F-Stop to 2.8 or even 3.0 to get more area of face in focus (my lens is F/2 at full open). However, the background bokeh is not much different.

DOF is the area that's in focus. It covers the entire FOV, part of the FOV.

Not talking about DOF at all here.

Well.... then in return... i also not understand what u are trying to explain tho..

Not that easy to explain, not without a graph / diagram. I'm not going to put that much effort just to explain.

Small matter, don't care what others think. Just go shoot and be happy.

"Compression" is dependent on distance alone. Not focal length.

Cuba try test.

1. using 50mm lens, subject (let say ur GF) at 10m from the camera.
2. same spot but using 200mm lens

compare both images...
-obviously FOV would be different.
-crop (and enlarge) the image taken using 50mm lens such that FOV will be the same as image taken with 200mm lens.
-Compare any background object relative to the subject..

After that u will agree with me

This post has been edited by OOtaii: Dec 23 2016, 08:53 PM

Never disagreed with you guys in the first place.

I think you guys are missing my point here entirely. Like I said, I see where you guys are coming from.

The earlier part I mentioned is as what you guys mentioned, and also seen in this article. https://photographylife.com/what-is-lens-compression

The cropped area (aka same FOV) part it will look same (as what I mentioned earlier)

If you guys noticed, I've not once said any of you are wrong because if you go buy that viewpoint that "based on crop area" then I don't disagree at all - the compression for that area is same because it's same distance between camera to subject.

The thing is this - will you say 24mm and 90mm have same compression? No one will say that, because that focal length will lead to different distance and how light is captured thus the subject looks different.

You guys totally missed my 3rd line, and mistake on my part of not making it more clear as well.

In any case, this is why when explaining focal lengths, people say they will result in different compression and perspective rather than a lengthy "oh if you stand same distance and crop that area compression is same". That's why I said one can't just compare based on the 'cropped area' earlier.

For the sake of proving that compression is distance based, no doubt but in the end even with the results you can't say both lens have same compression. They don't. Shooting at 24mm and 90mm the difference is there.

Hahahahaha finally ayam bought 50mm

Hopes it going to be worth buying it

I got Sigma 50mm 1.4 non art, thinking of selling it and getting Nikon 35mm 1.8g.

Any idea

I have a 35mm and it looks good on the overall performance (Remark: mine is 35mm F1.8)

I didn't vote any length as the focal length are entirely depends how is your style of portrait shooting is.

35mm gives you the freedom to stay up close or set a distance between yourself and the subject. 50mm is a a challenging length to play around. Not impossible but will have to be creative with it.

Try both focal length and decide from there, use the retail assistant as your subject of test

I used to have this dilemma as well. Then I bought all three 35mm 1.8, 50mm 1.4, and a 85mm 1.8.

I found out that I used the 50mm most, followed by the 85mm on my DX (Nikon D80) camera. Almost never touched the 35mm.

Recently I bought a 2nd hand full frame D700 (awesome camera!). Then I found myself using mostly the 85mm