Minimum Aperture

[Anteaus]

Hello All. I have a D7000 with 35mm 1.8G prime. I think I already know the answer to this but I wanted to ask anyway. I want to increase depth of field, and I know that in order to do this I need to decrease the diameter of the aperture. The camera won't let me make it smaller than F/22. Is there any other way to increase depth of field or am I at the physical limits of this particular lens?

I know this won't make for a good exposure, I'm just trying to learn a bit more about what my camera can do.

 

[Syborg1211]

Check out this other thread that's going on that gives lots of great insight into increasing DOF:

http://forums.anandtech.com/showthread.php?t=2240209

The distance you are from the subject affects how much aperture affects DOF, so if you take some steps back, you'll gain some DOF and get more in focus.

 

[Anteaus]

Thanks

 

[SecurityTheatre]

Realistically, without making the subject smaller in the frame, you need a different lens.

Generally, the minimum aperture is related to the maximum aperture (it's not a rule, but a trend). A 1.8 lens will only go to f/22. A f/5.6 lens will often go to f/32. Some macro lenses will do f/64. But really, past f/22 you're losing resolution to diffraction and f/64 is pretty soft on any camera.

There's always a trade off!

 

[Anteaus]

I realize that. I have my kit lens (18-105mm) for that. I'm just in the process of learning what my 35mm can do. I plan on using it as my primary travel lens so I don't think DOF will be a big issue unless I'm very close to the subject. It goes infinite with the subject around ~40' at f/5.

I found this great site for calculating DOF if anyone is interested.

http://www.dofmaster.com/dofjs.html

 

[Munky]

Check out the DOF calculator http://www.dofmaster.com/dofjs.html

DOF depends on several variables - aperture, focal length, focus distance. For example, you don't need to focus at infinity to have the DOF extend to infinity. Play around with different values to get a feel for it. On a crop sensor diffraction begins to set in at f11-f16, so I would think twice before pushing it all the way to f22 or smaller.

Edit: beat me to it.

 

[Anteaus]

Good point. Is it recommended that I stay in Aperture Priority mode then focused around F3.5 unless there isn't enough light? I read a review on this lens that stated that it is sharpest around there.

 

[SecurityTheatre]

I tend to prefer the blurred backgrounds as a matter of style, so I let the lenses run just slightly below their sharpest. They're usually adequate a stop below and still pretty damn good, but I have a D700 which has pretty large pixels anyway so it may not be as apparent as on a D7000. Regardless, for me, style and flexibility outweigh absolute sharpness any day.

If I was shooting with a 35mm f/1.8 I would be using it at f/2.0 a lot for isolating subjects and getting cool blur.

I would switch to maybe f/4-5.6 for everyday flexible stuff (prevents you from blowing the focus too often as well) and switch to f/11 or even f/16 if I'm doing architecture or want most everything in focus.

An yes, aperture priority is the best option for everyday shooting unless you want a specific shutter speed for something (like motion blur, or fast action)... and even then, aperture priority works if you watch the metering carefully.

At night, i often shoot in full manual because longer exposures (more than 1") start to mess up the metering. Of course, then you're using a tripod and shooting static shots anyway, so it's not as big an issue to try again if you miss the exposure.

Also, when you really need the light, don't be afraid to go to f/1.8. It's better than bumping the ISO up, or risking motion blur if you're getting under 1/60. Just do it. Those lenses are still damn good wide open.

Good luck!

 

[ElFenix]

you're at f/22 and you need more?

stand further away.

or buy a point & shoot.

 

[blastingcap]

The smaller the aperture the more diffraction. You will start losing sharpness after f/9.5 or f/11 or something like that, on your particular camera.

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

If you want really vast DoF you can always try a smaller sensor type, like MFT or Nikon 1 or even point and shoots.

 

[mchammer187]

At 35mm and f22 the hyperfocal distance is 6 ft to infinity so as long as you are 3.75 ft away from your foreground than everything you want will be in focus

edit that is for full frame:

for crop it is 4.73 Feet min distance and hyper focal distance is 9 ft

 

[iGas]

The smaller the aperture the more diffraction. You will start losing sharpness after f/9.5 or f/11 or something like that, on your particular camera.

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

If you want really vast DoF you can always try a smaller sensor type, like MFT or Nikon 1 or even point and shoots.

Agree, but at time you need/want that depth of field at close focus such as macro photography. I often shoot at f/11~f/16 in macro mode even those I sacrifice some sharpness to gain workable depth of field.

 

[SecurityTheatre]

The smaller the aperture the more diffraction. You will start losing sharpness after f/9.5 or f/11 or something like that, on your particular camera.

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

If you want really vast DoF you can always try a smaller sensor type, like MFT or Nikon 1 or even point and shoots.

It is better to sacrifice some to f/22 or f/32 diffraction than to go to a point-and-shoot (which will suffer from the same diffraction anyway, due to the small lens), in addition to the lower quality from a tiny sensor.