Macro Newbie Needs Help - Define Macro

[astrocom]

Hi, originally I was looking for the Nikon 85mm portrait lens.
Some digging and I got advise that the Tamron 90mm DI Macro is a better
buy since it offers 1:1 Macro.

Further digging and I come across that the Tamron 18-200 DI II Macro has a macro
ratio of 1:3.7, I am a little dizzy with the macro jargon. Can somebody give me the heads up about the ratio? Thanks in advance.

[Del_CtrlnoAlt]

Originally Posted by astrocom Hi, originally I was looking for the Nikon 85mm portrait lens. Some digging and I got advise that the Tamron 90mm DI Macro is a better buy since it offers 1:1 Macro. Further digging and I come across that the Tamron 18-200 DI II Macro has a macro ratio of 1:3.7, I am a little dizzy with the macro jargon. Can somebody give me the heads up about the ratio? Thanks in advance.

wrong section lah, here photo gallery...

anyway, ratio in this way, 1:1 is replication is 1:1 to a 35mm film (preferably slides), mean u take it 1:1 on 35mm slides you take the slide and u see that insect or watever, its 1:1 ratio

if you take 1:2 then its the real life one is 2x bigger than the slides, or the slides one is 1/2 the size of the real life one.

so 1:3.7 is.. u do your own maths..

on digital depending on your camera, like mine is 1.5x crop, so watever is 1.5x1:** (watever ratio it says...) so technically its 1.5:** but u can't possibly take the CCD out to compare... but its good that its more magnified...

[astrocom]

Heh heh...........my apologies to all the Macronauts here.
I'd appreciate if the mods could move this to the relevant section.

Thanks Del_CtrlnoAlt. Your explanation is clearer to me than what I tried to figure out
from some website.

[Del_CtrlnoAlt]

actually i also pian jiak 1...

i only summarize wat i learn from SLCC, Sulhan & Ortega... absorb abit here & there

[hwchoy]

sorry DCA, when you say 35mm "slide" you really meant 35mm film, yes? 1:1 means the image projected on the image plane is the same size as the subject itself. so an 18mm long spider would occupy half the wide of the actual film.

In the case of cropped sensors, the image would still occupy 18mm out of the 24mm sensor.

[Del_CtrlnoAlt]

Originally Posted by hwchoy sorry DCA, when you say 35mm "slide" you really meant 35mm film, yes? 1:1 means the image projected on the image plane is the same size as the subject itself. so an 18mm long spider would occupy half the wide of the actual film. In the case of cropped sensors, the image would still occupy 18mm out of the 24mm sensor.

cheem... but i thought it was so, but dunno much about the technicalities... but i thought 35mm slides (positive) is easier, cos u see via the light box can see exact mah, den most say film will think about negative, which cannot be viewed like that...

btw, ya, i think the 18mm long spider would still 'fill' 1:1 to the 24mm cropped sensor... but normally ppl say its like 1.5x of the 35mm sensor, so its like if equation goes, i should rephrase... 1.5x1:1 (on 35mm view...) hehe...

thanks for your clarification.

[hwchoy]

I didn't understand when you say slide since it can be projected or referring to the image on the slide itself (is it also 36x24mm ?). if they are the same just positive and negative then no difference lah.

what I meant about the cropped sensor, is that the image will appear as 18mm long, but the sensor is only 24mm hence the magnification appear larger (i.e. you have to factor in the cropping factor just like the focal length). this is how I understand it since 1:1 is a feature of the optical system and nothing to do with the sensor/film. should be easy to find out, I'll go shoot a ruler tonight on my 100mm macro lens.