Lmarc Loc: Ojojona, Honduras

After someone pointed me to the "depth of field calculator" online I found it invaluable. My wife just bought a new Sigma 70-300 "macro" zoom lens which has a switch that initiates the macro function when zoomed between 200-300mm. It works good for what it is supposed to do, I guess, and the lens in general is far better than I expected for the price.

Is there any way to calculate DOF when in the zoom macro mode? How can she increase DOF? Are there any tricks other than aperture adjustment?

:?: :?:

snowbear

DoF is also affected by the distance to the subject - the closer you are, the shallower the DoF. When the distance to the subject and aperture are the same, a longer focal length will produce a shallower DoF.
Here's a link that seems to give the formulae (yes, more than one) for DoF calculations: http://cameradojo.com/2011/07/08/how-to-calculate-depth-of-field/

I almost always use a tripod for closeups. I will also use the smallest practical aperture.

Consider looking for a focusing rail to fine tune the focus, and check into focus stacking (where you take multiple shots, each one focused ever-so-slightly behind the last). I haven't tried this yet, but am working on it.

martinfisherphoto Loc: Lake Placid Florida

Not for your DOF but if you have Mirror Lockup or can use a remote control to release your shutter or a Time delay, this will help keep your photos sharp. DOF is enough to fight with, don't need lens shake-blurr adding to your problems. I'm currently working on flower macro myself, the Mirror lockup has made a big difference in my sharpness, hope this helps.

Lmarc Loc: Ojojona, Honduras

Thank you very much for your reply and the link. I will check it out. I've done some focus stacking, and it works great for small objects and tabletop shots of jewelry and such. I use CombineZM, a free program that is very easy to use. It doesn't always work out like I want and may take a couple tries, but all in all a good program.

What I'm trying to do is find a way to use my wife's Sigma 70-300mm zoom on "macro" mode and get an entire flower or bug in focus. Those aren't usually subjects conducive to stacking. I know I can get a good shot from a distance, but I'd like to be able to crop as little as possible, hopefully salvaging at least 6mb out of the RAW 10.2. Not sure that's possible.

Lmarc Loc: Ojojona, Honduras

The Nikon D-60 doesn't have lockup, NOR auto-bracketing of different exposures for HDR. Nikon dropped the ball on both these, but it's a great little camera and I find it so easy to use. I use a tripod a lot along with remote release, which helps with focus a lot! DOF is my main problem. I think I've about got the focus monster whipped. :thumbup:

martinfisherphoto Loc: Lake Placid Florida

Hey I'm right behind you.. Thinking about the extension tubes as a cheap means of getting closer and better DOF. I posted some flowers yesterday I took with a 100mm, getting better but not where I want to be yet. Having fun trying, I know that.

snowbear

Keep in mind - the closer you get, the shallower the DOF.

martinfisherphoto Loc: Lake Placid Florida

Guess I should have said Higher magnification for lesser money.. I don't want to get closer in distance but closer in view.

docrob Loc: Durango, Colorado

Depth of field in macro work in my opinion is over-rated. More important in my experience is paying attention to the planes of focus that can be perceived from the camera postion and lens perspective. By taking your time, cultivating patience, quietly observing how the image shifts as you move - as the camera moves - as the subject moves and how the light moves.....Flowers are my passion - none of them have been captured with more than F8.

my first post - comments?

wesprostudios

So, here is the answer to your question. I have most of the other posts and I think they have answered it as well. DOF is controlled by first the size of the Aperture which is determined by the capability of your lens. It can also be determined by the distance from lens to the subject. In the case of Macro photography, your lens will have a minimum distance to your subject that it will automatically focus on your subject. An example of this would be, on your 70-300mm lens you may have a minimum focal point of 4.9 ft. This means, in order for the lens to automatically focus on the subject you will need to be a distance of at least 4.9 ft. from your subject. However, if you are trying to take macro photos using a zoom lens like the 70-300mm you should be able to achieve some amazing DOF. You are going to want to make sure you are shooting with a tripod to minimize camera shake. Let me know if this helps, there are ton of tips on DOF. When you mentioned macro and DOF, I think you are trying to create a bokeh effect where the background is completely blurred thus, leaving the subject in focus.

steve_stoneblossom Loc: Rhode Island, USA

If your objective is to create boken effect, the first and (sometimes) easiest step is to put some distance between the subject and the background. This will also enable smaller apertures, thereby enabling you to get the entire subject in focus.

Lmarc Loc: Ojojona, Honduras

Actually, the objective was to find a way to bring a whole flower, for example, into focus while using the "macro" mode of the 70-300mm zoom. By necessity it would be around three feet away at a nominal 300mm, but I don't know if all that applies with the macro mode.

steve_stoneblossom Loc: Rhode Island, USA

Yeah, I run into similar problems in macro. Sometimes it is difficult to get the entire flower in focus.

It is still best to use smallest efficient aperture (not necessarily f22, since diffraction may become an issue). Try 11 to 16.

Regarding shooting distance, you will find you are able to get more of the flower in focus by increasing the distance you shoot from. Think of the depth of field as a percentage, rather than a measurement of distance. For example, let's say you are shooting from a distance of 10 inches (close, I know, but bear with me). Your flower may be 3 inches across, so the distance from the front edge to the back might be almost 33% of your shooting distance. Now if you step back to a distance of 100 inches, there is only a 3% difference between the front and back edges.

I have the same lens, though almost certainly older. Tripod is almost certainly called for in this instance, and mirror lock-up, timed or remote shutter release will also help. Also, I use low ISO, reducing noise if cropping is needed.

K2KImages

Based on your situation, extension tubes will only make things worse. Tubes allow you to get closer which makes the DOF shallower. As far as cropping, shoot in raw and then you can crop with better success.

docrob Loc: Durango, Colorado