Good lens option for DSLR look?

[Adam Flaherty]

More and more clients are starting to request the DSLR shallow depth of field look. Depending on how much space I have in the location I'm shooting, I can sometimes achieve it, but sometimes the setting doesn't allow for it.

I've invested in two Z7U's in the past few years, and with all the money I've sunk into the cameras, cases, solid tripod heads and legs, etc, I haven't yet purchases any lenses (and frankly, I don't know a whole lot about them). Does anyone have a good recommendation for a lens that will give me the desired soft background effect, that's compatible with the Z7?

Thanks very much!

Adam Flaherty

AF MEDIA, LLC | HD Video Production | Maine NH MA Boston Videographer
http://www.facebook.com/AFlahertyMEdia

[Michael Bradshaw]

Hi Adam, the z7 has a 1/3 inch chip and won't give much depth of field unless you are working at the long end of the lens with the iris wide open. (2.0 for the z7 standard lens)

There are three factors which dictate dof. F-stop, focal length and sensor size. You can get a bit as I've mentioned above but I'm afraid the sensor size is a limiting factor.

Your only option would be to look at a letus adapter or similar. I've never had one so hopefully someone with more knowledge about it than me will appear.

Unfortunately the 35mm adapters are pricey and so are decent lenses. I have two z7's and ending up buying a vg10 to get some nice dof shoots when necessary. I'd love two fs100's but the price of them and also buying nice lenses would buy me a nice new car at that kind of money.

If anyone else has ideas I'd be curious too.

M.

[Zach Love]

"There are three factors which dictate dof. F-stop, focal length and sensor size."

This is a big & often repeated mistake. Sensor size has nothing to do with DOF. Sensor size has a lot to do with FOV (field of view).

If you keep the FOV & your f-stop the constant, but change your sensor size, then your DOF will change because the focal length of the lens will change, and when you change the focal length you change the DOF.

Adam, sorry to say, but there is no magic lens that will defy the laws of physics & give you that "DSLR" look on a Z7. So you can either zoom in & back far away, though I think the best bet is to get a 35mm adapter.

With everyone going to DSLRs, getting a used Letus or Red Rock M2 is a fraction of the price of what they were a couple years ago. Back in 2008 used ones sold for about 80% - 90% of new ones. Now you can get used ones for about 25-50% of a new set.

Lastly I'm just going to say that shallow DOF isn't the end all be all. I think many people over use it & don't use it well. It is a tool... shallow DOF vs deep DOF is similar to a fresnel vs a softbox... or a lav vs a shotgun mic. Different tools for different uses.

[Michael Bradshaw]

fair enough, but the orginal poster can't can't change the sensor size without buying a new camera. In a way sensor size does affect his obtainable dof because he is stuck with it.

M.

[Zach Love]

Yes, if you're looking for a wide FOV & a shallow DOF, you can't get it with a Z7 unless you use a Letus (or similar). Because of the 1/3" chips on a Z7, if you want a wide FOV you'll have a really short lens & with really short lenses you'll have really deep DOF.

DOF is 100% the physics of light. DOF is only changed by the length of a lens (the optics bend the light) & the f-stop (the iris funnels the light). A 1/3" chip, 2/3" chip, ASP-C sized chip, etc. does NOT in anyway shape or form mess with light. All a chip does is read the light that hits it & if it doesn't play around with the light, it can't adjust the DOF.

This is why chip size does not directly change the DOF.

Put a 50mm lens on a Z7 & put the same 50mm lens on a 7D with the same f-stop, you'll get the same DOF, but different FOV. The image will be "cropped" on the Z7 compared to the 7D.

The common perception that chip size changes DOF is because people assume that a lot of the variables are staying constant.

If you assume that the camera position is staying the same & the distance to the subject is staying the same & the f-stop is staying the same & the FOV is staying the same, then when you change the chip size, you have to change the length of the lens to make everything match. And when you change the length of the lense you change the DOF.

A+B+C+D=E If you keep "A" "B" & "C" constant & you change "D" then "E" has to change to keep the statement true.

So yes, the chip size "changed" the DOF, because everything else was kept constant. Thus, the chip size is the straw that broke the camels back. And the lesson is that the straw only has significant weight when you add everything else first. Take away everything else & the straw loses significance.

[Tom Hardwick]

Originally Posted by Michael Bradshaw

Hi Adam, the z7 has a 1/3 inch chip and won't give much depth of field unless you are working at the long end of the lens with the iris wide open. M.

I'm sure Michael meant to say ' ...1/3 inch chip and WILL give much depth of field'. And that's the rub - the Z7 is capable of giving the least dof of practically any 1/3" chipped camcorder simply because the standard 12x zoom is so long and fast.

So it's either a 35mm adapter, a vDSLR or the Panasonic 4/3rds lump.

tom.