1.4 what is the use?

W00DY · February 12, 2007

Ok, this is sort of a little embarrising asking this, since I have been taking photos for quite some time and should know the answer... but, I have a 50mm 1.4 nikon lens (great lens, love it, very sharp) But what I don't get is what is the use of 1.4?

I know it allows you to have a faster shutter speed in low light but every time I use it there is not enough DOF to be useful.

For instance, if I take a photo of a face the nose will be in focus, maybe the eyes (I know you should always focus on the eyes but this is just for this example) but the rest of the face (ie: ears) will be out of focus, sometimes even the eyes, depending on the size of the person's nose :rofl

So my question to everyone, in what situation would you use 1.4 if it limits the amount of DOF so much?

Looking forward to an explanation so I can start using my lens correctly :rolleyes

Cheers.

Malte · February 12, 2007

It's very useful for placing... well focus on something. Say a portrait with nose and ears out of focus and eyes in perfect focus.

Malte

Mike Lane · February 12, 2007

The DOF will be greater as the subject moves farther back from the lens. So say you're shooting some pics of a dimly lit party or something (uh I don't know, it could happen right

) where the subjects aren't 2 feet from the lens you'll get a more useable DOF.

claudermilk · February 12, 2007

Distance helps. I have been able to use Canon's 85/1.2 wide open in smaller theater venues with great results. The amazing lightbucket qualities allow flashless shooting in a very dark show; it does challenge the AF capability, but when you get it right on the results can be amazing. I plan to eventually replace my 50/1.8 with a 1.4 to gain the 1/3 (?) stop...and better build and AF motor.

wxwax · February 12, 2007

Mike Lane wrote:

The DOF will be greater as the subject moves farther back from the lens. So say you're shooting some pics of a dimly lit party or something (uh I don't know, it could happen right ) where the subjects aren't 2 feet from the lens you'll get a more useable DOF.

Very useful for shooting concerts in dim clubs, for example.

Mitchell · February 12, 2007

Don't be embarrassed. This is actually a good question.

You own a great piece of glass that will allow you to shoot in low light situations.

It also is nice for portraits. If you can nail the eyes, the results can be quite striking with a nice bokeh all around the subject.

This one was taken with a Nikon 85mm at f1.4

You can also have some depth of field fun if the subject warrants it.

Your lens will take some practice with it's thin depth of field at f1.4, but the results can be worth it.

Shay Stephens · February 12, 2007

There is a two fold advantage. And both are important to me. Firstly, low light focus is improved with a 1.4 lens even if that aperture is not used. Secondly, when using f/1.4 it allows hand held usage in crazy low light. When the option is to get a photo with small DOF or no photo at all, I would choose the one with small DOF ;-)

DoctorIt · February 12, 2007

Ah, but remember, your camera always focuses at the largest aperture - the most light. So whether you want your shot at f/4 or f/16, when you are composing and focusing, you are looking through the lens at f/1.4. Having that much light lets the camera focus faster.

mercphoto · February 12, 2007

DoctorIt wrote:

Ah, but remember, your camera always focuses at the largest aperture - the most light. So whether you want your shot at f/4 or f/16, when you are composing and focusing, you are looking through the lens at f/1.4. Having that much light lets the camera focus faster.

Not only faster, but more accurately. Since the DOF at 1.4 is so shallow, that also means the image goes out of focus faster on the focus sensor itself, making the camera focus more accurately with a 1.4 lens than a 2.8, or especially than a 5.6 lens. Exposure metering is also done at 1.4, letting more light hit the exposure meter which should make for a more accurate calculation. Lastly, your viewfinder is brighter, making it easier to see what you are shooting.

Lots of reasons to like fast glass even if you never shoot under f/8.

wxwax · February 12, 2007

Shay Stephens wrote:

There is a two fold advantage. And both are important to me. Firstly, low light focus is improved with a 1.4 lens even if that aperture is not used.

Good one, forgot to mention that.

Rhuarc · February 12, 2007

DoctorIt wrote:

Ah, but remember, your camera always focuses at the largest aperture - the most light. So whether you want your shot at f/4 or f/16, when you are composing and focusing, you are looking through the lens at f/1.4. Having that much light lets the camera focus faster.

I did not know this. I'll have to keep this mind mind. Thanks!

maddernc · February 12, 2007

mercphoto wrote:

Not only faster, but more accurately. Since the DOF at 1.4 is so shallow, that also means the image goes out of focus faster on the focus sensor itself, making the camera focus more accurately with a 1.4 lens than a 2.8, or especially than a 5.6 lens. Exposure metering is also done at 1.4, letting more light hit the exposure meter which should make for a more accurate calculation. Lastly, your viewfinder is brighter, making it easier to see what you are shooting.

Lots of reasons to like fast glass even if you never shoot under f/8.

Excellent, that statement shall hopefully be the argument that nails me the f2.8 70-200 IS rather than the f4 IS version. My partner and I are having an ongoing debate as to which to get for an upcoming trip.

Cain

wxwax · February 12, 2007

maddernc wrote:

Excellent, that statement shall hopefully be the argument that nails me the f2.8 70-200 IS rather than the f4 IS version. My partner and I are having an ongoing debate as to which to get for an upcoming trip.

Cain

Bring your biceps, there's quite a weight difference between the two (as you may already know

)

maddernc · February 12, 2007

wxwax wrote:

Bring your biceps, there's quite a weight difference between the two (as you may already know )

Howdy Sid

Not to hijack thread but the weight is the main discussion point. We already have the hefty 100-400 IS so my partner is keen on the lighter f4. I say bring on the 2.8!!

Cain

wxwax · February 12, 2007

maddernc wrote:

Howdy Sid

Not to hijack thread but the weight is the main discussion point. We already have the hefty 100-400 IS so my partner is keen on the lighter f4. I say bring on the 2.8!!

Cain

I've never regretted more speed, have often regretted less speed. I say go for it!

Nikolai · February 12, 2007

Cain,

maddernc wrote:

Howdy Sid

Not to hijack thread but the weight is the main discussion point. We already have the hefty 100-400 IS so my partner is keen on the lighter f4. I say bring on the 2.8!!

Cain

I have both 100-400 IS and 70-200 f/2.8 IS. Great combo!
When I use them in parallel I'm also adding a TCx1.4 (with taped pins) to 100-400, thus having 70-200 and 140-560. Now that's a range:-)

jdryan3 · February 12, 2007

wxwax wrote:

I've never regretted more speed, have often regretted less speed. I say go for it!

Fred Maurer · February 12, 2007

Very timely question for me!
This past weekend I was asked to shoot some photos in a local music club "In the Round". Didn't know what to expect so I brought a pack full of lenses, from 24 to 200 mm, 1.4 to 2.8. Fastest lens was the 50/1.4. I arrived and asked the owner what he was going to do for lighting and he said that was it. It was a 60W bulb in a lamp on a table! I felt sick for a few minutes, thought about leaving, and then put all the lenses away and stuck with the 50/1.4. It was like shooting in candlelight!
(all iso=3200)

(OK - I guess you can figure out why I didn't leave!)

W00DY · February 13, 2007

Thanks for all the replies.. I guess I need to use the lens more.

I have gotten some great portraits out of the lens, just never at 1.4. For example I took some good shots of a spider and only the body was in focus, not the legs... pumping up the aperture would not have allowed me to get the shot.

The comments regarding distance are interseting though, maybe this is where I am going wrong. I'm off to practise.

Cheers.

LiquidAir · February 14, 2007

W00DY wrote:

Thanks for all the replies.. I guess I need to use the lens more.

I have gotten some great portraits out of the lens, just never at 1.4. For example I took some good shots of a spider and only the body was in focus, not the legs... pumping up the aperture would not have allowed me to get the shot.

The comments regarding distance are interseting though, maybe this is where I am going wrong. I'm off to practise.

Cheers.

Depth of Field is determined by two things: apeture and magnification. Magnification is actually the bigger effect.

Which of these two shots was at the wider apeture?

The first one is at f/2. The second one is at f/1.4. Despite being shot a stop wider open, the second shot has much wider DoF because I am not framing my suject as tightly. When I have sufficient light I usually shoot tight headshots like the first one at f/5.6 or f/8. On a full body shot, f/2 is usually just fine and I rarely stop down past f/4.

I only use f/1.4 when I really need it not so much for the DoF but because the lenses I have (35 and 50) get quite soft that wide open. The second shot was ISO 1600 f/1.4 1/60s. In this case I think it gave me a better result than any of the other (rather limited) options.

cabbey · February 16, 2007

LiquidAir wrote:

Depth of Field is determined by two things: apeture and magnification. Magnification is actually the bigger effect.

By 'magnification' do you mean "distance to focal point"? That's the textbook definition of the components of DoF I learned ages ago.

Which of these two shots was at the wider apeture?

The first one is at f/2. The second one is at f/1.4. Despite being shot a stop wider open, the second shot has much wider DoF because I am not framing my suject as tightly.

Well, I got the right answer when I guessed, but for a different reason.

I assumed from the shots that the second one was taken from farther away than the first, thus even though it was a larger aperture, it had a deeper DoF. (I also assumed from the way you asked what the answer would be.

To illustrate the impact of the focal depth on the total depth of field, pull up your favorite DoF calculator and set it to your favorite prime, I'll use a 50mm lens at f2.0, then walk the distance to subject out and look at the total DoF:

@  1m focal distance, DoF = 0.050m
@  2m focal distance, DoF = 0.206m
@  4m focal distance, DoF = 0.843m
@  8m focal distance, DoF = 3.513m
@ 16m focal distance, DoF = 16.379m
@ 32m focal distance, DoF = 187.088m
@ 64m focal distance, DoF = &#8773;&#8734;

As you can see, each time I doubled the focal distance, the total DoF *more* than doubled; it looks to me like an approximately O(n²) growth curve.

kres · February 23, 2007

cabbey wrote:

To illustrate the impact of the focal depth on the total depth of field, pull up your favorite DoF calculator and set it to your favorite prime, I'll use a 50mm lens at f2.0, then walk the distance to subject out and look at the total DoF...

Anyone intrested in this conversation, and the technicalities of Digital photography owes it to themself to check out the link above - it's a great breakdown of a complex set of topics.

!

Thanks for sharing it.

1.4 what is the use?

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