It's not really the lens Joan, unless you are getting closer than the lenses closest focusing distance? A heavier SLR is harder to hand hold than a rangefinder or compact, so you are more likely to get camera shake. The old recommendation was hand hold at no slower shutter speed than the focal length of the lens on 35mm SLR film cameras. For example a 60mm lens no slower than 1/60th second, a 200mm lens no slower than 1/200th of a second.
But some argue that as APS sized DSLR's sensors are smaller than 35mm film, meaning the image and any blur caused by shake is enlarged more in the final reproduction, this formula should be multiplied by the cameras crop factor since the same focal length lens has a narrower angle of view and behaves like a longer focal length lens would on 35mm film regarding shake.
Therefore the 60mm behaves for shake like a 90mm on a Nikon APS sensored camera due to it's 1.5 crop factor, so no slower than 1/90th of a second. A Canon with a 1.6 crop factor like a 96mm, so no slower than 1/96th of a second, or the nearest shutter speed above. On a tripod you can use the slower speeds OK.
The problem is that may stop you using smaller apertures for increased depth of field, unless you use higher ISO settings and loose quality, which is the reason many use flash because this allows smaller f-stops whilst also stopping action because the flash pulse is very short.
Another reason is you are often in uncomfortable positions trying to get close up, which are not the best for holding a camera steady. Conventional photography allows you to stand up and brace yourself when using slower speeds.
I did notice when Nikola changed from a compact to a DSLR with a macro lens it took him a while to get used to it until his close-up's were as good as on his compact camera. Now there is no difference and they are as superb as they used to be.
See:-
http://www.all-things-photography.com/h ... n-slr.html
http://digital-photography-school.com/b ... al-camera/
http://tech.yahoo.com/gd/dealing-with-d ... ake/153019
http://members.shaw.ca/clives/photoguide2.html
http://64.78.42.182/sweethaven/MiscTech ... 5&lesNum=1
DaveW