Macro: Depth of Field

vaper · 09-21-2012, 07:54 AM

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How does focal length affect macro depth of field? Assuming 1:1 magnification and using the same aperture, will a 35mm macro lens yield a deeper depth of field than a 105mm macro lens?

Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?)

Lastly, does a 1:1 full frame macro lens give a greater magnification when used on aps-c cameras?

JinDesu · 09-21-2012, 07:57 AM

My understanding is that - at macro range, it's the magnification that defines the DOF, not the focal length.

On an APS-C camera, a macro lens will project a 1-1 image onto the sensor. Full frame lenses will project the full 35mm image, but the sensor only picks up a portion of that. Therefore, the image is still 1-1, but cropped (and therefore will seem more magnified).

Docrwm · 09-21-2012, 08:02 AM

Macro photos usually require high f-stop settings to achieve adequate depth of field. You can make the most of what little depth of field you have by aligning the subject matter with the plane of sharpest focus. In genuine macro work depth of field is independent of focal length; a 100 mm lens at 0.5X therefore has the same depth of field as a 35 mm lens at 0.5X, as long as they are at the same f-stop. Also, unlike with non-macro photography, the depth of field remains symmetric around the focusing distance (front and rear depth of field are equal).

elliott · 09-21-2012, 08:54 AM

Originally posted by vaper

Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?)

Any online DOF calculator will be able to tell you. There are also plenty of macro calculators for determining working distance and amount of extension required for the magnification level you want.

**x-country** · 09-21-2012, 09:20 AM - **1 Like**

The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22

and this is @ f18

vladimiroltean · 09-21-2012, 10:16 AM

Originally posted by x-country

The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22

and this is @ f18

Nice strap! I have one for my SP1000. Did you find it for sale new, or was is from an old film camera?

Docrwm · 09-21-2012, 10:22 AM

Originally posted by kcobain1992

Nice strap! I have one for my SP1000. Did you find it for sale new, or was is from an old film camera?

Kood Pentax Logo Digital / Film Camera Strap - 3/8" Webbing - UK | eBay
7 UK pounds plus shipping

newarts · 09-21-2012, 10:29 AM

Originally posted by vaper

How does focal length affect macro depth of field? Assuming 1:1 magnification and using the same aperture, will a 35mm macro lens yield a deeper depth of field than a 105mm macro lens?

No.

Quote:

Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?)

1mm x 11/2.8 = 3.9mm

Quote:

Lastly, does a 1:1 full frame macro lens give a greater magnification when used on aps-c cameras?

Same magnification on the sensor.

Dave

Anvh · 09-21-2012, 10:29 AM

Originally posted by JinDesu

My understanding is that - at macro range, it's the magnification that defines the DOF, not the focal length.

On an APS-C camera, a macro lens will project a 1-1 image onto the sensor. Full frame lenses will project the full 35mm image, but the sensor only picks up a portion of that. Therefore, the image is still 1-1, but cropped (and therefore will seem more magnified).

It's actually always magnification that defines the DOF but some find it easier to say focal length and focus distance instead of magnification.

With macro the pupil magnification is important, therefore the standard online calculators won't work for macro, this one will work http://toothwalker.org/optics/vwdof.html

This might help you further
http://toothwalker.org/optics/dof.html

vladimiroltean · 09-21-2012, 10:32 AM

Originally posted by Docrwm

Kood Pentax Logo Digital / Film Camera Strap - 3/8" Webbing - UK | eBay
7 UK pounds plus shipping

Well well, who would have told!
Thanks for the link and sorry for the offtopic.

vaper · 09-21-2012, 11:18 AM

Thanks for all your responses.

imtheguy · 09-21-2012, 12:53 PM

Originally posted by x-country

The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22

and this is @ f18

Being the gear head I am, your sample shots look amazingly attractive. Far nicer than the models at the Pentax booth Photokina.

L33tGreg · 09-21-2012, 03:45 PM

Originally posted by newarts

No.

1mm x 11/2.8 = 3.9mm

Same magnification on the sensor.

Dave

I suspect it's actually 4mm. F/2.8 is actually. It is F/(sqrt(2)^3) (squareroot of 2 all to the 3rd power). F/11 is derived similarly. I may be talking out of my @$$.

vaper · 09-21-2012, 04:43 PM

Originally posted by L33tGreg

I suspect it's actually 4mm. F/2.8 is actually. It is F/(sqrt(2)^3) (squareroot of 2 all to the 3rd power). F/11 is derived similarly. I may be talking out of my @$$.

"did you remember to carry the bump? good." (who knows the obscure reference?)

**x-country** · 09-22-2012, 01:07 AM

Originally posted by imtheguy

Being the gear head I am, your sample shots look amazingly attractive. Far nicer than the models at the Pentax booth Photokina.

Thank you very much.

09-21-2012, 07:54 AM	#1
vaper Junior Member Join Date: Mar 2012 Posts: 32	Macro: Depth of Field Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here. How does focal length affect macro depth of field? Assuming 1:1 magnification and using the same aperture, will a 35mm macro lens yield a deeper depth of field than a 105mm macro lens? Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?) Lastly, does a 1:1 full frame macro lens give a greater magnification when used on aps-c cameras?

09-21-2012, 10:29 AM	#9
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Originally posted by JinDesu My understanding is that - at macro range, it's the magnification that defines the DOF, not the focal length. On an APS-C camera, a macro lens will project a 1-1 image onto the sensor. Full frame lenses will project the full 35mm image, but the sensor only picks up a portion of that. Therefore, the image is still 1-1, but cropped (and therefore will seem more magnified). It's actually always magnification that defines the DOF but some find it easier to say focal length and focus distance instead of magnification. With macro the pupil magnification is important, therefore the standard online calculators won't work for macro, this one will work http://toothwalker.org/optics/vwdof.html This might help you further http://toothwalker.org/optics/dof.html Last edited by Anvh; 09-21-2012 at 10:59 AM.

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09-21-2012, 07:57 AM	#2
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	My understanding is that - at macro range, it's the magnification that defines the DOF, not the focal length. On an APS-C camera, a macro lens will project a 1-1 image onto the sensor. Full frame lenses will project the full 35mm image, but the sensor only picks up a portion of that. Therefore, the image is still 1-1, but cropped (and therefore will seem more magnified).

09-21-2012, 08:02 AM	#3
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Macro photos usually require high f-stop settings to achieve adequate depth of field. You can make the most of what little depth of field you have by aligning the subject matter with the plane of sharpest focus. In genuine macro work depth of field is independent of focal length; a 100 mm lens at 0.5X therefore has the same depth of field as a 35 mm lens at 0.5X, as long as they are at the same f-stop. Also, unlike with non-macro photography, the depth of field remains symmetric around the focusing distance (front and rear depth of field are equal).

09-21-2012, 08:54 AM	#4
elliott Inactive Account Join Date: Dec 2008 Location: North Carolina Photos: Albums Posts: 1,720	Originally posted by vaper Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?) Any online DOF calculator will be able to tell you. There are also plenty of macro calculators for determining working distance and amount of extension required for the magnification level you want.

09-21-2012, 09:20 AM - 1 Like	#5
x-country Site Supporter Join Date: Dec 2009 Location: Frösön (Östersund) Posts: 69	The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22 and this is @ f18

09-21-2012, 10:16 AM	#6
vladimiroltean Veteran Member Join Date: Dec 2010 Location: Bucharest, Romania Photos: Gallery Posts: 1,465	Originally posted by x-country The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22 and this is @ f18 Nice strap! I have one for my SP1000. Did you find it for sale new, or was is from an old film camera?

09-21-2012, 10:22 AM	#7
Docrwm Veteran Member Join Date: Sep 2010 Location: Somewhere in the Southern US Photos: Gallery \| Albums Posts: 12,285	Originally posted by kcobain1992 Nice strap! I have one for my SP1000. Did you find it for sale new, or was is from an old film camera? Kood Pentax Logo Digital / Film Camera Strap - 3/8" Webbing - UK \| eBay 7 UK pounds plus shipping

09-21-2012, 10:29 AM	#8
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by vaper How does focal length affect macro depth of field? Assuming 1:1 magnification and using the same aperture, will a 35mm macro lens yield a deeper depth of field than a 105mm macro lens? No. Quote: Also, is there any compiled data relating to macro depth of field at various aperture settings? ( if f2.8 yields a 1mm 'slice' of focus, what would f11 yield?) 1mm x 11/2.8 = 3.9mm Quote: Lastly, does a 1:1 full frame macro lens give a greater magnification when used on aps-c cameras? Same magnification on the sensor. Dave

09-21-2012, 10:32 AM	#10
vladimiroltean Veteran Member Join Date: Dec 2010 Location: Bucharest, Romania Photos: Gallery Posts: 1,465	Originally posted by Docrwm Kood Pentax Logo Digital / Film Camera Strap - 3/8" Webbing - UK \| eBay 7 UK pounds plus shipping Well well, who would have told! Thanks for the link and sorry for the offtopic.

09-21-2012, 11:18 AM	#11
vaper Junior Member Join Date: Mar 2012 Posts: 32 Original Poster	Thanks for all your responses.

09-21-2012, 12:53 PM	#12
imtheguy Site Supporter Join Date: Mar 2009 Location: Virginia Beach Photos: Gallery \| Albums Posts: 2,950	Originally posted by x-country The 35 Macro Limited gives you a nice perspective as you can come up really close on objects. This is @ f22 and this is @ f18 Being the gear head I am, your sample shots look amazingly attractive. Far nicer than the models at the Pentax booth Photokina.

09-21-2012, 03:45 PM	#13
L33tGreg Veteran Member Join Date: Jan 2011 Location: Charleston, SC Photos: Gallery Posts: 369	Originally posted by newarts No. 1mm x 11/2.8 = 3.9mm Same magnification on the sensor. Dave I suspect it's actually 4mm. F/2.8 is actually. It is F/(sqrt(2)^3) (squareroot of 2 all to the 3rd power). F/11 is derived similarly. I may be talking out of my @$$.

09-21-2012, 04:43 PM	#14
vaper Junior Member Join Date: Mar 2012 Posts: 32 Original Poster	Originally posted by L33tGreg I suspect it's actually 4mm. F/2.8 is actually. It is F/(sqrt(2)^3) (squareroot of 2 all to the 3rd power). F/11 is derived similarly. I may be talking out of my @$$. "did you remember to carry the bump? good." (who knows the obscure reference?)

09-22-2012, 01:07 AM	#15
x-country Site Supporter Join Date: Dec 2009 Location: Frösön (Östersund) Posts: 69	Originally posted by imtheguy Being the gear head I am, your sample shots look amazingly attractive. Far nicer than the models at the Pentax booth Photokina. Thank you very much.