Help with Macro lens DOF

[Kethaneni]

I am only able to get a very thin frame in sharp focus with my Sigma Macro lens on my D60. I can either get the eyes of the insects in focus or the body and the same with flowers, either I get the petals or the core. Am I doing anything wrong? Any help in this regard would be greatly appreciated.

 

[Josh66]

Am I doing anything wrong?

No, that's pretty much normal...

What aperture are you using? Stopping down will help, but even then - it's still going to be pretty thin.

If you can get the subject more parallel to the film plane, that will help too.

 

[Hardrock]

Or a small aperature like 22f and a flash.

 

[djacobox372]

This is why you see macro setups with two powerful flashes... you need to shoot at a very small aperture.

 

[Big Mike]

Yup...the DOF gets thin as you get closer to your subject...and at Macro distances, it's razor thin. The way to increase your DOF is to 'stop down' the lens (use a smaller aperture). Of course, as you stop down the lens, you need to either increase the exposure time (probably requiring a tripod) or you need to add more light (flash etc).

 

[tirediron]

Try plugging different numbers into this on-line depth-of-field calculator. It will help you get a better understanding of just how little room you have to work with, even at the smallest apertures.

 

[Overread]

Or a small aperature like 22f and a flash.

Sort of true - you do want to shoot with the smaller apertures (bigger f numbers) to get as much depth of field as you can into the shot. However most macro shooters consider f16 to be the smallest they will go, with many sticking to f13 as a standard smallest size. This is because at around 16 Diffraction will start to take place, its not too bad (in most lenses) at f16, but go smaller (Say to f22) and it will start to make a noticable difference by giving you softer images.

This is why you see macro setups with two powerful flashes... you need to shoot at a very small aperture.

Actually macro flashes don't have to have that much power - since they are often very close to the subject - many ringflashes and twinlight setups are not that high in guide numbers (compared to say a 580EX speedlite) but they are enough for lighting many macro scenes.
Flash is an important consideration for macro if you intend to shoot without a tripod, or if your shooting highly mobile insects (where subject movement makes a tripod impractical most times).

 

[Hardrock]

Or a small aperature like 22f and a flash.

Sort of true - you do want to shoot with the smaller apertures (bigger f numbers) to get as much depth of field as you can into the shot. However most macro shooters consider f16 to be the smallest they will go, with many sticking to f13 as a standard smallest size. This is because at around 16 Diffraction will start to take place, its not too bad (in most lenses) at f16, but go smaller (Say to f22) and it will start to make a noticable difference by giving you softer images.

This is why you see macro setups with two powerful flashes... you need to shoot at a very small aperture.

Actually macro flashes don't have to have that much power - since they are often very close to the subject - many ringflashes and twinlight setups are not that high in guide numbers (compared to say a 580EX speedlite) but they are enough for lighting many macro scenes.
Flash is an important consideration for macro if you intend to shoot without a tripod, or if your shooting highly mobile insects (where subject movement makes a tripod impractical most times).

Interesting I will try f16 or f13 with my flash. Thanks Overread!

 

[JerryPH]

F/11-F/13 seems to be the sweet spot for sharpness with my Sigma 105mm F/2.8 macro.

 

[Kethaneni]

Thanks everyone, I feel a lot better noweacesign: (worried that I suck at macro). It is really very hard to take macro pictures (especially of bugs) with a tripod, but will try next time.
Thanks again for all your help.

 

[Phranquey]

Sort of true - you do want to shoot with the smaller apertures (bigger f numbers) to get as much depth of field as you can into the shot. However most macro shooters consider f16 to be the smallest they will go, with many sticking to f13 as a standard smallest size.

Phhhhtttttttt........:greenpbl:

DOF is definitely also a function of distance. The closer you get, the thinner your DOF is going to get, even stopping down. The following 3 pics were taken at successively closer distances AND gradually stopped down.

f/40...taken from a few feet away.

f/43

f/45

 

[Garbz]

This is because at around 16 Diffraction will start to take place, its not too bad (in most lenses) at f16, but go smaller (Say to f22) and it will start to make a noticable difference by giving you softer images.

Very close, but diffraction is a function of primarily sensor size, as f/22 on two different 105mm lenses would produce the same diffraction because of the same aperture.

A lens that you say shouldn't go above f/16 (I say f/13 myself) could quite easily be taken a stop higher on an FX camera before diffraction plays the same role in reduced sharpness.

 

[Overread]

Ahh a good point about sensor size, though I also recall being told that the larger the sensor size the less depth of field you get in a shot - so whilst you gain a stop against diffraction (And also gain in a larger sensor size) you lose a bit of depth as well.

However I do know that quite a few "pro" macro shooters are into the larger camera formats for their shooting, the abilty to get more bug in a shot at a fixed magnifaction is not something to passup.

Phranquey is mad by the way - and has silly sick apertures to work with (I don't think any of my macro lenses can close down that far!)

 

[djacobox372]

Ahh a good point about sensor size, though I also recall being told that the larger the sensor size the less depth of field you get in a shot - so whilst you gain a stop against diffraction (And also gain in a larger sensor size) you lose a bit of depth as well.

However I do know that quite a few "pro" macro shooters are into the larger camera formats for their shooting, the abilty to get more bug in a shot at a fixed magnifaction is not something to passup.

Phranquey is mad by the way - and has silly sick apertures to work with (I don't think any of my macro lenses can close down that far!)

Sensor size has no effect on dof--it just crops the image.

Of course, since dof gets tighter as focal lengths go up, and a crop body sensor will allow you to use a smaller focal length to achieve the same magnification of a full size sensor it may appear that the crop sensor has wider dof--but it's no different then if that lens and aperture were used on a full-frame camera (you'd just have less magnification).