What lens I need to take detailed photos of lashes?

I want to make macro photos of lashes like this:

Per the EXIF, that photo was taken with an 100mm f/2.8.

Yes, but it was taken by 500D that is not fullframe, so there is crop-factor and I'm not sure, if I can make the same photo with fullframe camera, if that lens allow you to go closer.

That can be done with a 100mm macro, any other true macro lens or a decent quality prime lens (85mm.1.8 for example) and a full set of Kenko extension tubes.

100mm Macro, 60mm Macro, Or a lens with extention tubes.

The " crop factor" has zero bearing on what you are talking about; yes, the 100mm macro will do shots like that for you.

It would still be possible on FF, but you would be nearer to the minimum focusing distance. The 100/2.8 macro will allow you to go to 1:1 reproduction at the sensor, so the full field at 1:1 will be 24mm x 36mm on FF. Plus, you can always crop it a bit more afterwards.

But lens that I'm about to buy can focus from 40 cm, not from 30 cm like Canon EF 100mm f/2,8 Macro. Will it be a problem?

LittleMole wrote in post #14818192
But lens that I'm about to buy can focus from 40 cm, not from 30 cm like Canon EF 100mm f/2,8 Macro. Will it be a problem?

The important question isn't as to how close a lens can focus, but its maximum magnification ratio.

For instance, a Canon APS-C body (22.2mm wide sensor) with a 15-85 lens (which has a MM ratio of 0.21) should be able to focus on something that's 22.2mm/0.21=105.7mm wide. Indeed, if I lay a rule down on a table and try to focus on it, that's about as much magnification as I can get. With a macro lens (that has a 1:1 reproduction - i.e. 1.00 MM ratio) you can photograph something that's 22.2/1.00=22.2mm wide.

Think of your minimum focusing distance as your working distance. A 100mm macro lens that claims 1:1 will have a closer minimum focussing distance than a 180mm macro lens that is 1:1. Because 180mm is more telephoto, it can still give you 1:1 reproduction, but doesn't need to get as close. So, the longer focal length lens gives you more effective working distance, whilst still giving 1:1 reproduction.

You mention you have an offer for a 100mm macro lens. If it's a true macro lens (i.e. 1:1 reproduction), and its minimum focussing distance is 40cm, then you can assume it'll give you 1:1 at 40cm. As you have a FF body, that means an object around 36mm wide will fill the frame width. That should be pretty much spot on to take a shot of an adult's eye that completely covers the frame.

Yeah, I finally understand it. Tomorrow i will buy that 100mm lens. Thank you all guys (especially sploo)!!

LittleMole wrote in post #14818154
Yes, but it was taken by 500D that is not fullframe, so there is crop-factor and I'm not sure, if I can make the same photo with fullframe camera, if that lens allow you to go closer.

I think some one says you can get close enough with FF.

What needs to be considered here is the DOF. The crop camera will get you a much deeper DOF given the same F-stop and with intent to filling the frame with the eye. Looks like about a 1/2 inch "in focus" depth on the picture. If you have a full frame, you will be getting about 1/4 inch "in focus" or will need to change to a higher f-stop... maybe a 1.5 stop difference.

I am told that all macro lenses will do 1:1 (lifesize), its only the field of view that varies and that really only affects backgrounds. How true that is I'm not thr right person to judge.

Naturally I'd go for a longer focal length macro so I was shooting from slightly further away.

As snake0ape says, DoF is the big problem, no matter which lens it is. f/16 is really the limit, any wider and DoF is so thin as to be non existant.

LittleMole wrote in post #14818311
Yeah, I finally understand it. Tomorrow i will buy that 100mm lens. Thank you all guys (especially sploo)!!

You're welcome

snake0ape wrote in post #14819913
...What needs to be considered here is the DOF...

Using http://www.dofmaster.c​om/dofjs.html I see that a 7D with a 100mm lens at f8 and 40cm distance to subject gives about 0.36cm of DOF. The same details for a 5D give 0.58cm DOF. I suspect the fact that the 100mm lens on the 7D gives the same fov as a 160mm has a bearing on the apparent DOF.

Remember though that DOF is very theoretical, and based on acceptable sharpness for a certain sized print viewed at a certain distance by a person with good eyesight (can't remember the defaults off the top of my head). If you were planning on printing huge, then you'd need more DOF to maintain apparent sharpness.

Lowner wrote in post #14819992
I am told that all macro lenses will do 1:1 (lifesize), its only the field of view that varies and that really only affects backgrounds. How true that is I'm not thr right person to judge.

Naturally I'd go for a longer focal length macro so I was shooting from slightly further away.

As snake0ape says, DoF is the big problem, no matter which lens it is. f/16 is really the limit, any wider and DoF is so thin as to be non existant.

I think there are some 50mm 'macro' lenses that are actually only 1:2 (i.e. half life sized). But, with pretty much any lens you can add extension tubes to reduce the minimum focussing distance and thus increasing magnification. As you say, the longer focal lengths allow more distance to the subject, so I'd expect a 50mm 1:2 macro with enough extension to get to 1:1 may have very little working room.

sploo wrote in post #14820053
Remember though that DOF is very theoretical, and based on acceptable sharpness for a certain sized print viewed at a certain distance by a person with good eyesight (can't remember the defaults off the top of my head). If you were planning on printing huge, then you'd need more DOF to maintain apparent sharpness.

That may be true with normal images, but my admittedly limited macro experience is that once outside that DoF, the blurring is immediate and pretty total. And we also know everyone peers closely at interesting images.

Lowner wrote in post #14820273
That may be true with normal images, but my admittedly limited macro experience is that once outside that DoF, the blurring is immediate and pretty total. And we also know everyone peers closely at interesting images.

I think the issue is that "that DoF" is the depth that's considered to be acceptably in focus (so, yes, anything outside the DOF region would be soft). I don't know how the sharpness falls off as you move away from the focus point though (whether it's linear or some form of bell curve) - or even if it changes shape depending on the focus distance.

I do understand that when you get very close (focussing distance) the DOF and hyperfocal distance calculations tend to go "a bit weird". I guess with such shallow DOF at macro distances it's going to drop away quickly (i.e. a very steep curve from out-of-focus to in focus to out-of-focus).

What I meant by apparent DOF is that it's all down to circle of confusion calculations; and stricter values would need to be applied when printing larger, which has the effect of making your acceptable DOF shallower. Therefore if printing very large it may be necessary to stop down further - though I guess that at some point diffraction softness sets in and robs the whole image of sharpness. That's why the landscape pros love tilt/shift lenses, as they can control the plane of focus to squeeze out more usable DOF without stopping down into the diffraction region.