Bad DOF on kit lens? at DVinfo.net

Robert Kirkpatrick · September 1st, 2009, 04:36 PM

I just read over at prolost that the kit lens (28-135mm f/3.5-5.6 IS USM Standard Zoom) won't have a great shallow DOF. (Or I may be reading it wrong -- sometimes, the tech side confuses me.) Is this correct? If I'm reading it (and the comments) correctly, they are saying that there will be a shallow DOF on close-ups but wide shots will be still fairly deep focus (not much blurred).

I'm new to this whole video dslr thing -- so sorry if my questions seem, uh, dumb.... I've tried reading all the recent posts -- and I've checked out all the current vids (what little there are), but the vids don't say what lens are used, and I'm starting to confuse myself... Thanks.

Michael Richard · September 1st, 2009, 04:54 PM

for best depth of field you want F1.2, 1.4 , 1.8, 2.8. as you move up the aperture scale DOF becomes more difficult to achieve. The kit lens zoomed out at 5.6 wouldn't give you any.
Some fast primes are a good idea, and fast zooms F2.8 L variety.

Phil Hover · September 1st, 2009, 06:00 PM

before I went all nikon - I had the 28-135 and it has pretty good shallow dof zoomed - a good price in the kit as well.

Matt Newcomb · September 1st, 2009, 06:07 PM

I was just debating getting the body only and finding a better lens. Can anyone link to a decent one?

Phil Hover · September 1st, 2009, 06:39 PM

FM Reviews - Main Index

Josh Dahlberg · September 2nd, 2009, 04:13 PM

Quote:

Originally Posted by Phil Hover

before I went all nikon - I had the 28-135 and it has pretty good shallow dof zoomed - a good price in the kit as well.

I also had this lens previously... and it's really pretty good. Apart from the varying aperture and build quality, I personally didn't find it lacking vis-a-vis the 24-105L. I agree for the kit price it's a steal. You'll get your money back selling second hand if you don't like it.

The biggest problem with this zoom is there's no wide end to speak of on a crop sensor camera... the wide end is where I'm really going to lament switching from a 5Dm2 to the 7D. My 20mm prime becomes a 32mm :-(

Ron German · September 3rd, 2009, 08:05 AM

And what about the Tamron AF 28-75mm f/2.8 XR Di LD Aspherical (IF) Autofocus Lens?
Is it apropriated to work with the crop sensor D7?
Thanks
Ron

Bill Pryor · September 3rd, 2009, 09:18 AM

I have a Tamron 17-35 DG lens, works fine on my 20D, same size chip. Any lens with a Canon mount will work. All 35mm Canon camera EF lenses work, as well as the EF-S lenses and the comparable lenses from Tamron, Sigma, etc. The only limitation is that on the lenss designed for APS-C cameras, they won't work on 35mm size chip cameras like the 5D.

Ron German · September 3rd, 2009, 02:53 PM

Thank you Bill
Do you know if Tamron AF 28-75mm f/2.8 XR Di LD Aspherical (IF) is designed for APS-C or full frame cameras?
Ron

Bill Pryor · September 4th, 2009, 02:18 PM

I think the Di lenses are for APS-C cameras, DG are for full frame. But the DG works on both sizes, just like Canon EF lenses. I like my 17-35, very nice and sharp and well built, but really heavy. I bought full frame lenses because I had in the back of my mind that I might get a 5D MKII one of these days. Now with the 7D almost out, that's the way I'll go if I upgrade my still photo system. The lenses I have will be fine, but the Di lenses are lighter weight, and in the case of the Tamron, there's a 17-50 that's f2.8 all the way. Mine is only 2.8 at the wide end.

Jim Snow · September 6th, 2009, 09:37 AM

The choice of f-stop is a matter of degree with respect to the amount of shallow depth of field that you want to use. From a creative perspective you may want a slight softening of the background or in other cases, a complete blur. Lower f-stops allow a more complete blur. Pro photographers often use f-stops as high as 5.6 or more when they only want to soften the background rather than blur it into indistinction. The requirements for each shot vary. That's one of the reasons why pro photographers usually have an assortment of lens.

In shots where you want an extremely out of focus background, you will find a lens that is faster than f 3.5 useful. But even if you have a f 1.1 lens, there will be plenty of shallow depth of fields shots where you want a more subtle control of background focus. In those cases, you will find f 3.5 to f 5.6 more appropriate. For example if you want to use shallow depth of field to switch attention between two subjects when one is closer than the other, you don't want to blur the other character to the point that they aren't recognizable. You just want to soften the focus a bit. In that type of shooting situation, f 1.1 or even f 2 would be too much.

The other use of fast lens is for low light shots. In those cases, shallow depth of field can be a liability that makes focus control more difficult especially when you want to have multiple subjects in focus that are at varying distances from the camera.

Bill Pryor · September 6th, 2009, 10:12 AM

Well said. Anybody who watches movies in theaters knows that every shot doesn't have a blurred background. It's an effect that is distracting if overused (as they often do on TV shows by shifting focus back and forth on a 2-shot as the characters speak--once is OK, any more is as annoying as overuse of a zoom).

There are some things I shoot regularly where I deliberately blur the background to hide some items the client may not want to identify. With the XH A1 I do this by moving in slightly closer and adding a .3 ND over and above the built-in maximum ND, and by shooting at -3db I can usually be wide open or nearly so, and this gives me what I need. With my still camera even with a 3.5 lens, it's easier to do the same thing because of the larger chip. I do have a 50mm 1.8 for low light situations, and it is an excellent portrait lens on an APS-C size camera.

September 1st, 2009, 04:36 PM	#1
Robert Kirkpatrick Regular Crew Join Date: May 2004 Location: Little Rock, AR Posts: 199	Bad DOF on kit lens? I just read over at prolost that the kit lens (28-135mm f/3.5-5.6 IS USM Standard Zoom) won't have a great shallow DOF. (Or I may be reading it wrong -- sometimes, the tech side confuses me.) Is this correct? If I'm reading it (and the comments) correctly, they are saying that there will be a shallow DOF on close-ups but wide shots will be still fairly deep focus (not much blurred). I'm new to this whole video dslr thing -- so sorry if my questions seem, uh, dumb.... I've tried reading all the recent posts -- and I've checked out all the current vids (what little there are), but the vids don't say what lens are used, and I'm starting to confuse myself... Thanks.

September 1st, 2009, 06:07 PM	#4
Matt Newcomb Major Player Join Date: Mar 2007 Location: Los Angeles, CA Posts: 212	I was just debating getting the body only and finding a better lens. Can anyone link to a decent one? __________________ Talenos Productions at http://www.talenos.com

September 1st, 2009, 04:54 PM	#2
Michael Richard Regular Crew Join Date: Dec 2003 Location: Midcoast, Maine Posts: 89	for best depth of field you want F1.2, 1.4 , 1.8, 2.8. as you move up the aperture scale DOF becomes more difficult to achieve. The kit lens zoomed out at 5.6 wouldn't give you any. Some fast primes are a good idea, and fast zooms F2.8 L variety.

September 1st, 2009, 06:00 PM	#3
Phil Hover Regular Crew Join Date: Jan 2006 Location: Costa Mesa, The OC, CA Posts: 87	before I went all nikon - I had the 28-135 and it has pretty good shallow dof zoomed - a good price in the kit as well.

September 1st, 2009, 06:39 PM	#5
Phil Hover Regular Crew Join Date: Jan 2006 Location: Costa Mesa, The OC, CA Posts: 87	FM Reviews - Main Index

September 3rd, 2009, 08:05 AM	#7
Ron German Major Player Join Date: Feb 2005 Location: Rio de Janeiro - Brasil Posts: 304	And what about the Tamron AF 28-75mm f/2.8 XR Di LD Aspherical (IF) Autofocus Lens? Is it apropriated to work with the crop sensor D7? Thanks Ron

September 3rd, 2009, 09:18 AM	#8
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	I have a Tamron 17-35 DG lens, works fine on my 20D, same size chip. Any lens with a Canon mount will work. All 35mm Canon camera EF lenses work, as well as the EF-S lenses and the comparable lenses from Tamron, Sigma, etc. The only limitation is that on the lenss designed for APS-C cameras, they won't work on 35mm size chip cameras like the 5D.

September 3rd, 2009, 02:53 PM	#9
Ron German Major Player Join Date: Feb 2005 Location: Rio de Janeiro - Brasil Posts: 304	Thank you Bill Do you know if Tamron AF 28-75mm f/2.8 XR Di LD Aspherical (IF) is designed for APS-C or full frame cameras? Ron

September 4th, 2009, 02:18 PM	#10
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	I think the Di lenses are for APS-C cameras, DG are for full frame. But the DG works on both sizes, just like Canon EF lenses. I like my 17-35, very nice and sharp and well built, but really heavy. I bought full frame lenses because I had in the back of my mind that I might get a 5D MKII one of these days. Now with the 7D almost out, that's the way I'll go if I upgrade my still photo system. The lenses I have will be fine, but the Di lenses are lighter weight, and in the case of the Tamron, there's a 17-50 that's f2.8 all the way. Mine is only 2.8 at the wide end.

September 6th, 2009, 09:37 AM	#11
Jim Snow Trustee Join Date: Mar 2009 Location: Santa Clara, CA Posts: 1,104	The choice of f-stop is a matter of degree with respect to the amount of shallow depth of field that you want to use. From a creative perspective you may want a slight softening of the background or in other cases, a complete blur. Lower f-stops allow a more complete blur. Pro photographers often use f-stops as high as 5.6 or more when they only want to soften the background rather than blur it into indistinction. The requirements for each shot vary. That's one of the reasons why pro photographers usually have an assortment of lens. In shots where you want an extremely out of focus background, you will find a lens that is faster than f 3.5 useful. But even if you have a f 1.1 lens, there will be plenty of shallow depth of fields shots where you want a more subtle control of background focus. In those cases, you will find f 3.5 to f 5.6 more appropriate. For example if you want to use shallow depth of field to switch attention between two subjects when one is closer than the other, you don't want to blur the other character to the point that they aren't recognizable. You just want to soften the focus a bit. In that type of shooting situation, f 1.1 or even f 2 would be too much. The other use of fast lens is for low light shots. In those cases, shallow depth of field can be a liability that makes focus control more difficult especially when you want to have multiple subjects in focus that are at varying distances from the camera.

September 6th, 2009, 10:12 AM	#12
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Well said. Anybody who watches movies in theaters knows that every shot doesn't have a blurred background. It's an effect that is distracting if overused (as they often do on TV shows by shifting focus back and forth on a 2-shot as the characters speak--once is OK, any more is as annoying as overuse of a zoom). There are some things I shoot regularly where I deliberately blur the background to hide some items the client may not want to identify. With the XH A1 I do this by moving in slightly closer and adding a .3 ND over and above the built-in maximum ND, and by shooting at -3db I can usually be wide open or nearly so, and this gives me what I need. With my still camera even with a 3.5 lens, it's easier to do the same thing because of the larger chip. I do have a 50mm 1.8 for low light situations, and it is an excellent portrait lens on an APS-C size camera.