Control of depth of field with the D60

[Steve13285]

I could be mistaken, but the question I read was:

"will I be able to blur the background of a portrait ..."

Eamon said:

"it's not as easy to get blurred backgrounds with the D-SLRs you mentioned ..."

My response to this is that is completely false in my experience. I have a large portfolio of shots that demonstrate this, and if anything I have had problems with so much blur that I have to lower the aperature to levels I'd rather not just to limit the blur.

Examples:





I've got dozens more. These shot with a Sigma 70-200 2.8 on a Canon D30 - most F8 I believe.

Not looking for commentary on quality or composition - just showing shallow DOF.
Steve

 

[Stephen Cook]

Depth of field was one of the terrific things about the D30. I have a 28-135 and a 50 1.4. Particularly with the 50 1.4, you can get terrific control of depth of field. Also, you will be able to shoot in low light situations that would require flash on the Coolpix series. I don't know if the 800 had it, but my 990 produced the worst red-eye in the history of the world with flash. Kind of like "Night of the Living Dead."

I've dickered back and forth with lenses. At first I was disappointed in the 28-135, but now that I have the 50 1.4, I don't try to make the 28-135 do things it really wasn't meant to do (indoors, low light), and I'm using and enjoying it much more now.

To answer your specific question, I think you'll be overjoyed by the DOF control of the D60, if it is anything like the D30. Don't have a clue about the D100, but I abandoned the Nikon camp because I just couldn't wait any longer for a sub $3000 digital slr. Love the Canon, and probably won't go back, but I still have great respect for Nikon products.

I currently shoot with a Nikon CoolPix 800, with a 2X zoom. I have
no control of DOF. I am hoping to improve that with the lenses
available with either the D60 or the D100.

 

[Daniel Lauring]

You can get blur. Eamon said that. He said there is less blur than an equivalent 35mm. He is totally correct.

It is simple as this. The larger the sensor, the smaller the depth of field.

35mm sensors (in this case, film) is larger than the D60, therefore they will have a larger DOF.

Danny

I could be mistaken, but the question I read was:

"will I be able to blur the background of a portrait ..."

Eamon said:

"it's not as easy to get blurred backgrounds with the D-SLRs you
mentioned ..."

My response to this is that is completely false in my experience.

 

[Daniel Lauring]

Misspoke that last line. A 35mm will have less DOF than a digital because it's sensor is bigger. Likewise, large format cameras have less DOF than 35mm. It is a fact of optics.

Danny

It is simple as this. The larger the sensor, the smaller the depth
of field.

35mm sensors (in this case, film) is larger than the D60, therefore
they will have a larger DOF.

Danny

I could be mistaken, but the question I read was:

"will I be able to blur the background of a portrait ..."

Eamon said:

"it's not as easy to get blurred backgrounds with the D-SLRs you
mentioned ..."

My response to this is that is completely false in my experience.

 

[Christopher Glaeser]

I could be mistaken, but the question I read was:

"will I be able to blur the background of a portrait ..."

Eamon said:

"it's not as easy to get blurred backgrounds with the D-SLRs you
mentioned ..."

My response to this is that is completely false in my experience.
I have a large portfolio of shots that demonstrate this, and if
anything I have had problems with so much blur that I have to lower
the aperature to levels I'd rather not just to limit the blur.

In fairness to Eamon, he did say that DOF could be limited with a D-SLR, and he said so in the second half of the sentence that was deleted. His complete sentence was, "Compared to 35mm cameras, it's not as easy to get blurred backgrounds with the D-SLRs you mentioned, but it can still be done relatively effectively." He was basically making the point that DOF could be limited in both 35mm and D-SLR, but it could be limited more in 35mm. Perhaps the confusion centers on the phrase "it's not as easy", which in this context means "the DOF will not be as small as 35mm", but interpreted differently, could mean something is difficult, to which you are replying, no, it's not difficult to blur the background. By my reading, I don't think Eamon meant to imply it was difficult to blur the background with 1.5x D-SLR, but merely that DOF would be larger with 1.5x D-SLR compared to 35mm. At least, that's the way I read it.

• Christopher

 

[LMC54]

Karl karl karl...I don't know where you get this WEIRD idea the CoC changes on a smaller format using a lens that is made for the 35mm format.... I would say forget it and shoot photos instead of misinforming people on your crazy notions. Funny how the DOF guide on my lens seems to be accurate on my D30 as on my 35mm film camera using the same lens...omg....!!!!
ROFL,
Larry

The simple and short answer is that as you said, to stand in the
same place and use a 1.6X shorter focal length, then open up the
Aperture 1-Stop (1.4X smaller F-number) if the lens will do it.
This will be "close enough" for all but the most critical of people.

The problem is too many people do not believe this answer. A large
number of people including Phil Askey (see:
http://www.dpreview.com/learn/Glossary/Optical/Depth_of_field_01.htm
under the DoF calculator) apparently, seem to think that the DoF
will be that of the shorter focal length lens, ignoring the fact
that the image will have to be enlarged more for the same size
output and this enlargement requires a smaller CoC (by the
enlargement amount). It is like the DoF equation did not have a
CoC.

As you seem aware, the classic DoF equation (for a "simple lens")
has 4 variables. Focal Length, Aperture Ratio = F-number,
Subject/focus distance, and Circle of Confusion (simplist to think
of as a sharpness metric). The First three terms are all Physics
and the laws of physics are not changed by using a smaller sensor.
But then we have that peskey CoC term. People that don't
understand it seem to want to just ignore it. Everything I have
read on the subject says that the CoC for the same size output
should be reduced by the amount that the sensor/film format is
reduced.

Karl

Your first sentence above should be "Yes, and the DoF will also be
different because ..."

in response to this:

No, the DoF will also be different because of the difference in
"format" size. For the same lens in a smaller film/sensor the
"Circle of confusion" will be smaller by the Difference in format
ratio. This is consitent with your later statement about Medium
format, just going in the other direction.

... I misunderstood the point you were making. I read that part of
your post too fast, for which I apologize. What you are really
saying is that because the smaller format image must be enlarged
more to achieve any given print size, the permissable circle of
confusion must be smaller and therefore DoF tables would be
different in the scenario I outlined. (This isn't technically what
you said -- technically, you said that the circle of confusion size
will be smaller, which is false -- but I know what you meant.)

Again, I tried to leave out the complications of enlargement ratio,
viewing distance, visual acuity etc. in my original statement. I
was responding to the statement that lens behavior is the same
regardless of format. This is true. The actual circles of
confusion formed by the lens (as distinct from "permissable circle
of confusion for perceived sharpness at any given print size and
viewing distance") are the same size for any lens used on any
format, if image magnification and effective aperture are constant
(leaving out the question of lens quality.) I was talking about
lens behavior because that was the specific question at issue; you
are talking about enlargement behavior, which is more important in
practical photographic terms (though both ways of talking about DoF
have their uses.)

 

[LMC54]

I'm tired of his foolishness. DOF with the same lens on both 35mm and D30 is identical. The guide on the lens is accurate for both....This is because the projection size is the same on both. And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[Karl Guttag]

I have been shooting some shots to prove some optical priciples of DoF. It so happens I had taken pretty much the situation you asked about and to which John and I both said that this is not right. Below is photographic evidence.

The top picture is an unscaled crop of a very sharp 50F1.4 at F22. The second picture is a 70-200F2.8L at 200F22 taken from the same place (70 inches from the center focus target) that I have scaled DOWN by 4X to make it the same size. The second target is 140 inches away.

http://www.fototime.com/ {FFC5130D-E705-43CD-A9D7-5CB68E974D83} picture.JPG

As you can clearly see, the DoF is much less even after scaling. The 70 inch target gets incrediably sharp (because it was scaled down, in point of fact the 50F1.4 lens is sharper unscaled to unscaled), but the 140 distance chart is still teribly out of focus even after scaling.

IF we do the math right, the 4X difference in Focal length would result in a 16X shorter DoF, but because we have scale the 200mm shot by 4X less we would "gain back" about 4X DoF or thus a net 4X less DoF.

Karl

In the questions that follow, assume:

• the same camera to subject distance
• the same 35mm film camera
• three lenses, 24mm, 50mm, 200mm

I think we can all agree that a cropped 35mm negative must be
enlarged more than an uncropped negative to produce the same size
print. Does more enlargement decrease DOF?

Someone posted recently that 24mm, 50mm, and 200mm lenses all have
the same DOF if they are all cropped to the same FOV and then all
enlarged to the same print size. In other words, he was claiming
that because the 24mm cropped image must be enlarged significantly
more than the 200mm uncropped image, the DOF of the 24mm image
would shrink to match the 200mm image. Comments?

• Christopher

 

[Doug Walker]

AGREED! There's a lot of "can't see the forest for the trees" thinking going on in this thread. The same lens on either a D30 or standard 35mm film camera will have the same depth of field. The only difference is the field of view. If you mount a 85m lens on a D30 thinking you now have a 135mm lens, the only thing that is different is the FOV. The DOF remains the same as the 85mm. This is no different than if you cropped the center of a 35mm negative to the size of the D30 sensor and then enlarged it. The DOF doesn't change.
Come on people, wake up! You're over analyzing.

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[Daniel Lauring]

Jeesh, calm down.

This can involve a lot of mathmatics, but if you sit back and relax and do a thought experiment, you will see the basic truth.

Look at these facts.

1. Consumer digicams have huge depths of field....much larger than 35mm. Their lenses are usually in the range of 7 to 20mm to be equivalent to 35mm to 115mm 35mm field of views. Some of these cameras have aperatures of F1.8 yet yield pictures with barely blurred backgrounds.

2. Large format cameras have very shallow depths of field. Their relatively long focal length lenses yield wide panaromic views...similar to much smaller focal length 35mm lenses.

Looking at these facts it is obvious that film size has an effect on depth of field...even if it is in a indirect manner.

Prosumer SLR digital cameras have smaller sensors than 35mm therefore they have larger depths of field. However, they are closer in size to a 35mm than they are to a consumer digicam therefore they have considerably less depth of field than a consumer digicam.

That is all most people want to know.

Danny

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[Daniel Lauring]

35mm has larger "sensor" therefore smaller depth of field. People are getting too worked up about this.

Danny

I could be mistaken, but the question I read was:

"will I be able to blur the background of a portrait ..."

Eamon said:

"it's not as easy to get blurred backgrounds with the D-SLRs you
mentioned ..."

My response to this is that is completely false in my experience.
I have a large portfolio of shots that demonstrate this, and if
anything I have had problems with so much blur that I have to lower
the aperature to levels I'd rather not just to limit the blur.

In fairness to Eamon, he did say that DOF could be limited with a
D-SLR, and he said so in the second half of the sentence that was
deleted. His complete sentence was, "Compared to 35mm cameras,
it's not as easy to get blurred backgrounds with the D-SLRs you
mentioned, but it can still be done relatively effectively." He
was basically making the point that DOF could be limited in both
35mm and D-SLR, but it could be limited more in 35mm. Perhaps the
confusion centers on the phrase "it's not as easy", which in this
context means "the DOF will not be as small as 35mm", but
interpreted differently, could mean something is difficult, to
which you are replying, no, it's not difficult to blur the
background. By my reading, I don't think Eamon meant to imply it
was difficult to blur the background with 1.5x D-SLR, but merely
that DOF would be larger with 1.5x D-SLR compared to 35mm. At
least, that's the way I read it.

• Christopher

 

[LMC54]

But Daniel...hehe relax ... the CoC doesn't change on the D30...this is where people get so fried in the head....I do alot of 4x5 photography and using smaller format backs.... and you know what? the DOF doesn't change...
Larry

This can involve a lot of mathmatics, but if you sit back and relax
and do a thought experiment, you will see the basic truth.

Look at these facts.

1. Consumer digicams have huge depths of field....much larger than
35mm. Their lenses are usually in the range of 7 to 20mm to be
equivalent to 35mm to 115mm 35mm field of views. Some of these
cameras have aperatures of F1.8 yet yield pictures with barely
blurred backgrounds.

2. Large format cameras have very shallow depths of field. Their
relatively long focal length lenses yield wide panaromic
views...similar to much smaller focal length 35mm lenses.

Looking at these facts it is obvious that film size has an effect
on depth of field...even if it is in a indirect manner.

Prosumer SLR digital cameras have smaller sensors than 35mm
therefore they have larger depths of field. However, they are
closer in size to a 35mm than they are to a consumer digicam
therefore they have considerably less depth of field than a
consumer digicam.

That is all most people want to know.

Danny

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[Daniel Lauring]

I don't understand why this should suprise people. Everyone knows consumer digicams, with their tiny lenses and sensors, have huge depths of field. Anyone familiar with large format cameras should know their large lenses have tiny depths of field. Calculating the exact effect requires lots of equations but the basic truth should be obvious. Larger sensor = smaller depth of field. To counter this effect, and get more blur, use a longer focal length lens and back up....just like you would do if you wanted more depth of field out of a 35mm.

Danny

The top picture is an unscaled crop of a very sharp 50F1.4 at F22.
The second picture is a 70-200F2.8L at 200F22 taken from the same
place (70 inches from the center focus target) that I have scaled
DOWN by 4X to make it the same size. The second target is 140
inches away.

http://www.fototime.com/ {FFC5130D-E705-43CD-A9D7-5CB68E974D83} picture.JPG

As you can clearly see, the DoF is much less even after scaling.
The 70 inch target gets incrediably sharp (because it was scaled
down, in point of fact the 50F1.4 lens is sharper unscaled to
unscaled), but the 140 distance chart is still teribly out of focus
even after scaling.

IF we do the math right, the 4X difference in Focal length would
result in a 16X shorter DoF, but because we have scale the 200mm
shot by 4X less we would "gain back" about 4X DoF or thus a net 4X
less DoF.

Karl

In the questions that follow, assume:

• the same camera to subject distance
• the same 35mm film camera
• three lenses, 24mm, 50mm, 200mm

I think we can all agree that a cropped 35mm negative must be
enlarged more than an uncropped negative to produce the same size
print. Does more enlargement decrease DOF?

Someone posted recently that 24mm, 50mm, and 200mm lenses all have
the same DOF if they are all cropped to the same FOV and then all
enlarged to the same print size. In other words, he was claiming
that because the 24mm cropped image must be enlarged significantly
more than the 200mm uncropped image, the DOF of the 24mm image
would shrink to match the 200mm image. Comments?

• Christopher

 

[Phred]

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

As far as CoC on the image plane is concerned that is correct. But unfortunately we don't leave the image there, we enlarge it, print it and then judge DoF based on what we see. And that my friend makes the smaller sensor inherently have less DoF than the larger (using the same lens).

Phred

 

[Doug Walker]

The consumer digicams you refer to have very small lenses. It's the design of these lenses that causes the large DOF not the sensor or the film size.

Let's not loose track of the constant here. The same lens on a D30 or a 35mm film camera will produce the same DOF. The only thing that is different is the FOV. For the same subject to camera distance, the same lens will produce the same DOF whether it's on a D30 or 35mm. If you change the subject to camera distance to compensate for the 1.6 difference then all bets are off. This is no different than if you changed the subject to camera distance on a 35mm camera, the focus point changes and so does DOF in that case.

This can involve a lot of mathmatics, but if you sit back and relax
and do a thought experiment, you will see the basic truth.

Look at these facts.

1. Consumer digicams have huge depths of field....much larger than
35mm. Their lenses are usually in the range of 7 to 20mm to be
equivalent to 35mm to 115mm 35mm field of views. Some of these
cameras have aperatures of F1.8 yet yield pictures with barely
blurred backgrounds.

2. Large format cameras have very shallow depths of field. Their
relatively long focal length lenses yield wide panaromic
views...similar to much smaller focal length 35mm lenses.

Looking at these facts it is obvious that film size has an effect
on depth of field...even if it is in a indirect manner.

Prosumer SLR digital cameras have smaller sensors than 35mm
therefore they have larger depths of field. However, they are
closer in size to a 35mm than they are to a consumer digicam
therefore they have considerably less depth of field than a
consumer digicam.

That is all most people want to know.

Danny

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[LMC54]

Hi Phred, Whatever bud....hehe I presume you believe in the toothfairy, too. So simple yet so hard to see....amazing how you guys shoot photos. Just amazing. Have a good day
larry

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

As far as CoC on the image plane is concerned that is correct. But
unfortunately we don't leave the image there, we enlarge it, print
it and then judge DoF based on what we see. And that my friend
makes the smaller sensor inherently have less DoF than the larger
(using the same lens).

Phred

 

[Daniel Lauring]

Forgive me if I'm off-base but when you are getting into tiny little differences who cares? DOF isn't exactly a exact science of "yes, that is perfectly out of focus."

Here are the two points to understand.

1. Going to a smaller format will yield larger depths of field. This is largely the effect of going to shorter focal length lenses to achieve the same perspective.

2. If you want less depth of field use a longer focal length lens and back up. You will, of course, be forced into a perspective change.

3. Putting 1 and 2 together, for the same perspective, a smaller format film will yield a larger depth of field.

Danny

This can involve a lot of mathmatics, but if you sit back and relax
and do a thought experiment, you will see the basic truth.

Look at these facts.

1. Consumer digicams have huge depths of field....much larger than
35mm. Their lenses are usually in the range of 7 to 20mm to be
equivalent to 35mm to 115mm 35mm field of views. Some of these
cameras have aperatures of F1.8 yet yield pictures with barely
blurred backgrounds.

2. Large format cameras have very shallow depths of field. Their
relatively long focal length lenses yield wide panaromic
views...similar to much smaller focal length 35mm lenses.

Looking at these facts it is obvious that film size has an effect
on depth of field...even if it is in a indirect manner.

Prosumer SLR digital cameras have smaller sensors than 35mm
therefore they have larger depths of field. However, they are
closer in size to a 35mm than they are to a consumer digicam
therefore they have considerably less depth of field than a
consumer digicam.

That is all most people want to know.

Danny

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[Doug Walker]

Enlarging does not change DOF. The original DOF in the image is constant. You may perceive it different, but it is constant.

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

As far as CoC on the image plane is concerned that is correct. But
unfortunately we don't leave the image there, we enlarge it, print
it and then judge DoF based on what we see. And that my friend
makes the smaller sensor inherently have less DoF than the larger
(using the same lens).

Phred

 

[LMC54]

Yup Doug, We are talking DOF here. nothing changes but the crop. That is all I'm saying. oh by the way just because you enlarge something doesn't mean the Depth of Field or "the Distance which is in focus" doesn't change... Amazing!!!!!!!!!!!!!!
Larry

This can involve a lot of mathmatics, but if you sit back and relax
and do a thought experiment, you will see the basic truth.

Look at these facts.

1. Consumer digicams have huge depths of field....much larger than
35mm. Their lenses are usually in the range of 7 to 20mm to be
equivalent to 35mm to 115mm 35mm field of views. Some of these
cameras have aperatures of F1.8 yet yield pictures with barely
blurred backgrounds.

2. Large format cameras have very shallow depths of field. Their
relatively long focal length lenses yield wide panaromic
views...similar to much smaller focal length 35mm lenses.

Looking at these facts it is obvious that film size has an effect
on depth of field...even if it is in a indirect manner.

Prosumer SLR digital cameras have smaller sensors than 35mm
therefore they have larger depths of field. However, they are
closer in size to a 35mm than they are to a consumer digicam
therefore they have considerably less depth of field than a
consumer digicam.

That is all most people want to know.

Danny

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

 

[LMC54]

Doug...ok whatever bud... do your thing.
Larry

I'm tired of his foolishness. DOF with the same lens on both 35mm
and D30 is identical. The guide on the lens is accurate for
both....This is because the projection size is the same on both.
And the only difference is the crop. so there!!! Karlg...get a life.
Larry!!!!!

As far as CoC on the image plane is concerned that is correct. But
unfortunately we don't leave the image there, we enlarge it, print
it and then judge DoF based on what we see. And that my friend
makes the smaller sensor inherently have less DoF than the larger
(using the same lens).

Phred