Can I get this kind of DOF out of the 35mm 1.8 DX???

Started Nov 12, 2012 | Discussions thread
primeshooter
Senior MemberPosts: 1,937
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Re: No, you can't. And not such bokeh either.
In reply to brightcolours, Nov 13, 2012

brightcolours wrote:

primeshooter wrote:

brightcolours wrote:

primeshooter wrote:

brightcolours wrote:

primeshooter wrote:

brightcolours wrote:

primeshooter wrote:

brightcolours wrote:

jamesorr wrote:

One of the types of photography I'm really attracted to is ridiculously shallow DOF work that pulls together people and nature, so last night when I found Elena Karagyozova's work featured on this site , I was extremely excited. In her interview she mentions that she uses the Nikkor 50mm 1.4 (there were a few when I looked it up) and Nikkor 85mm 1.8 on a full frame D800E.

I have the 35 1.8 DX for my D5100, which gives me that 50mm focal length, but not necessarily the same DOF since it's still technically a wider lens.

It is not about it being a wider lens. It is about that it has a smaller aperture. DOF is a function of the aperture.

Lets examine the aperture:

50mm f1.4: 50 / 1.4 = 35.7mm aperture.

35mm f1.8: 35 / 1.8 = 19.5mm aperture.

While the lenses will give a quite similar field of view on FF and APS-C respectively, the apertures are a lot different.

To get a similar DOF, you need a similar aperture. For 35mm that would mean 35mm focal length / 35mm aperture = f1

Nevertheless, I'm attaching one of the shots I REALLY love (there are a few) so you can see what I'm talking about. Have any of you been able to get this kind of DOF out of the 35mm 1.8? I guess I have when I'm, like, two feet away. I'm also a beginner and wonder if there might be some technique things I can employ here?

Another thing to consider is the relatively nice/smooth bokeh we see in this image. That is NOT possible with the Nikon AF-S 35mm f1.8 DX, because that lens has one of the worst bokeh characters I know.

A much better option for you will be the Sigma 30mm f1.4 EX DC. 30mm x 1.5 = 45mm, close enough to 50mm FF field of view wise

And aperture? 30 / 1.4 = 21.4mm aperture, a slight advantage over the Nikon 35mm f1.8. but with a MUCH nicer bokeh character, which is very important for such images.

Sorry, what you are saying is wrong. Dof isn't just a function of aperture alone...

I am not wrong. And it is. If you apply similar framing that is. I said aperture, not f-value.

What you have just said is like saying a cheese and tomato pizza is the same as a ham and pineapple pizza...

*as long as you change all the toppings.

Nonsense, dude. What I said is correct. That you can't get your head around it is fine, not my problem.

Regardless, I will try to make things a bit more clear to you.

It is NONSENSE to talk about DOF without considering the same framing of a subject. Without framing, it makes NO sense to talk about how lenses compare in certain ways (like DOF).

Further, that you think f-value and focal length determine the DOF, is fine. Those two determine the aperture size. That I say aperture size determines DOF is correct. Aperture size is what the f-value is about... focal length divided by f-value = aperture.

Well I disagree. It's not nonsense at all just your in your warped mind it is. You see subject to background distance affects dof yet you missed this out of your "equation". Your framing to your subject you could keep the same distance from camera to them - so the framing is constant, but walk them 100 metres away from the background to reduce the dof. There is a reason some pole shoot 4x5 and large format also, not just for the quality but sensor size increase and reduced dof ability this garners.

What do you say if someone asks you about a decent lens to isolate a subject and achieve a very shallow dof, do you say oh yeah framing is all that matters get a 50mm 1.4 and get right up in their face with it...

Or do you suggest a 135 f/2 or 200 f/2 and stand a bit further from their eyeballs?

You display a total ignorance of what actually is at play. Kind of silly.

Depth of focus has nothing to do with the distance of a background, it has to do with how quickly things get out of focus from the focus plane. In you stupid nonsense example you are just placing the background at a different distance to the subject, changing the scene itself. And then what exactly are you attributing to the lens? Its the changing scene.

More nonsense about 50mm f1.4's, you simply donot get what I wrote and display you ignorance in a very silly way.

I said framing has to be the same to compare, and it is about aperture (aperture determines the DOF).

50mm / 1.4 = 35.7mm aperture

135mm / 2 = 67.5mm aperture

200mm / 2 = 100mm aperture

The bigger the aperture, the more shallow the DOF.

Congratulations on dividing 135 by 2 and 200 by 2, that's awesome! A great technical analysis.

Wow, you are dense. By dividing by f-value, you get the aperture. And the aperture explains why you get a more shallow DOF with the 200m lens wide open than with the 135mm lens wide open.

But seriously, all the op want's to know how to achieve super shallow dof

Nonsense. That OP wanted to know how to achieve a similar image. He already understood the equivalent focal length for a similar field of view. I explained that you have to use a similar aperture to also get a similar DOF.

That you are too dense to understand what the OP is asking about, and too dense to understand what I write, should worry you.

- and if you do want to achieve that, you use a big sensor camera, stand the subject away from the background, get close to the subject, and use a large aperture lens with a long focal length. The fact that you want to keep framing the same when using a 50mm lens and a 400mm lens is your own problem - not sure why you would want to do this, but I can assure you it's certainly not what the op is meaning - just what you think he means.

You do not even know what framing means. Dense.

He wanted to know how to get a super shallow dof, not go to this location and shoot the exact same photograph. The small man resorts to insults...have a nice day.

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