Macro Lens - which focuses length, is in "theory" sharper lens?

I do not have any macro Lens and like to buy one. I am having very hard time to decide which one to buy first. I do know I can take the same 1:1 photo farer away with longer focused length macro lens than the shorter focused length macro lens.

My main question is: Which focuses length, is in "theory" sharper lens? Will 50mm macro lens have better picture quality than let say 200mm macro lens when taking the same picture with everything else stay the same?

My second question is: Which lens will have “deeper” depth of the field and which will have shallower depth of field?

Thank you very much for the help. I am newcomer to the photo world. I need a lot of help and learning. Yee

The DOF question is an interesting one, because the normal "rule of thumb" will break down. If the magnification is the same - that is, the image is the same size in all cases, then the DOF of all the lenses will be the same. The perspective will change because the lens to subject distance will change to keep the magnification constant.

In practice all the proper macro lenses should give superb results, but as the 50mm may well be a slightly simpler construction (fewer elements) then it just might appear to be better because of increased contrast and reduced flare. But really this is quibbling to a large degree.

A macro lens is a superb tool and will also work very well as a general purpose lens of the same focal length. So think about what else you might want to use it for and also what macro working distances would be best for the sort of macro shots you take. These factors will be more relevant than any quality considerations.

John

John is absolutley correct DOF will be identical no matter what focal length is used, won't go into detail why. Theoretically the closer you get to any subject the better the image will be but with macro, if not just for still objects flowers etc, bugs sometimes don't let you get that close so you may want to favour a 100mm over a 50mm. A 50mm is the ideal portrait length if you want versatility

Generally people are advised to buy the longest macro they can afford an din this case, Minolta 300/4, Nikon 300/4, Canon 180/3.5 and Sigma 180/3.5 are the only choices. I have both Minolta and Canon 100/2.8 macro. Both are ultrasharp lenses but the shallow DOF and weight always make me being too lazy to carry them around. I bought Minolta 50/2.8 and was surprised to find its sharpness being beyond my imagination.

Yee, you've already got comprehensive answers regarding DOF question.

I'm warning you about focus length/sharpness relationship: let's watch this real-world tests

http://www.nnplus.de/macro/Macro100E.html

Really interesting! There is no direct relationship between sharpness and focal lenght, but some lenses are better than other, of course.