MACRO LENSE FOR 10D

[station]

WHILE ATTEMPTING TO PHOTOGRAPH AN EGG FOR THE COMMERCIAL FORUM IT BECAME VERY APPARENT THAT I SHOULD INVEST IN A MACRO LENSE. WILL THE 1.6 RATIO OF THE 10D AFFECT THE IMAGE QUALITY AND MINIMUM FOCUSING DISTANCE OF THE CANON 100mm MACRO.

[jfrancho]

No, and no. What will change is the field of view (FOV). Before getting my macro, I used a a telephoto zoom lens (Tamron 28-300) with good results. I still use it occasionally for closeups, and stopped down a bit, makes great images. Also, consider the Sigma 105 macro in your decision.

[Max@Home]

Hi Station,

as I said: better, more and faster responses overhere

I agree with jfrancho, the 1.6x crop ratio of the 10D will not affect image quality, only the FoV will change.
The minimum focussing distance remains the same, but since you use a 'cropped' camera, the objects appear larger in the viewfinder.
(which might give you some additional working space, depending on the subject this *might* be handy for *you* )

Another option (on decent lenses) are the Canon screw-in macro lenses 250D and 500D, I have seen great results with these too!

...hope this helps you further, *my* €0.02 worth...

Kindest regards!

Max@Home

[keithallenlaw]

Greetings,

I purchased the 100mm macro and used it on my 30D and was very satisfied once I learned to use this very thin focal plain lens.
Only then when I got the 5D did this lens really shine. Now this is only my personal opinion, but I like this lens on my 5D better.
But, I believe the the focal plain is wider on the 30D because you are back further from the subject. I'm only speculating as why.
Truly a magnificent lens. I wish I had more time to spend with it....

-keith

[jfrancho]

DOF will be greater with a full frame camera, if all else is equal.

[JohnC]

Originally Posted by jfrancho

DOF will be greater with a full frame camera, if all else is equal.

I'm not quite sure how true that is when you get into macro territory (and by macro, I'm using the traditional 1:1 magnification or greater definition). What happens with Macro and a cropped sensor is that you get less image at 1:1 because the sensor is smaller. You are going to have the same distance between camera and subject at 1:1 with a given focal length lens, no matter what the film/sensor size. It is just that with a full frame 35mm size sensor you fill the frame with something that is about 1x1.5 inches. On a smaller sensor camera at 1:1 you will end up cutting off the edges of a subject that size.

The camera to subject distance has not changed. The magnification is the same. I think the DOF should be the same.

Many people now call "close up" photography "macro." They just mean that you can focus on something less than 10X the focal length away from the camera, even if it is less magnification than 1:1. There you may find differences in DOF because you are actually getting less magnification with the cropped camera to get the same field of view.

Macro lenses do NOT have less depth of field that "normal" lenses. They may be better corrected for work at closer distances. They may have a flatter plane of focus. But those don't change DOF. The shallow depth of field in closeup/macro work is because of higher magnification. And you would get the same DOF with a "normal" lens and extension tubes or closeup lenses.

And at 1:1 the DOF should be the same with a 50mm lens, a 100mm lens, or a 180mm lens. But there is actually a situation where the longer lens would give you MORE depth of field. This has to do with the construction of the lens and entrance/exit pupil sizes. I'll try to find a reference to that and give a link in a follow up message.

Just more stuff to think about....

John

[JohnC]

Here is a good reference on DOF: http://www.pinnipedia.org/optics/dof.html


See the section titled "DOF at constant magnification III" for the discussion of lens construction and macro DOF.

JC

[keithallenlaw]

LOL...I was replying to you post and a message came up that there was a new post occurring, great feature.
Yes, that was a great read. Still curious if this effects the focal plain depth, crop verses f/f.
Now to your link I go...

-keith

[jfrancho]

The camera to subject distance has not changed. The magnification is the same. I think the DOF should be the same.

The math here says otherwise. Remember DOF is somewhat subjective, as range of acceptable sharpness may vary by viewer, lighting, medium, etc. However, the article John linked to makes some sense with regards to lens construction, though the author doesn't give an indication as to how close is "close." While the EF 100mm f/2.8 Macro can get in close, it isn't real close, but it is close enough to just get to 1:1. Even with all that theory, I'd be curious if a real world test reveals the true answer. I find it hard to believe that the difference in c (10D = 0.019; 5D = 0.03) doesn't have any effect on DOF when it is measured in mere millimeters when this close. But, it is probably so close, most of us can't tell. Thanks for the link, John.

[Max@Home]

...would this help

quote

Depth of field is constant when the f-stop is proportional to the format size, i.e., DOF is the same for a 35mm image taken at f/11, a 6x7 image at f/22, a 4x5 image at f/45 or an 8x10 image at f/90.

unquote

Kindest regards,,

Max@Home

[station]

A BIG THANKS TO EVERYONE WHO REPLIED TO MY POST, THERE IS PLENTY OF SOUND ADVICE FOR ME. THANKS AGAIN DAVID C.