Macro lens ratios.

[Keith]

I have no doubt the answer to this question will be a lot less straighjt forward than I hope.

As I have not yet purchased my macro lens (got the funds, still not decided which), I still play at macro using a 1x4 close up filter attached to a Nikon 18-200mm lens used at 200mm.

The lens itself produces images at 1:4.5 ratio.
Does that mean a 1x4 close up filter attached will give me a 1:1 result at 200mm?

I have never had the chance to see what a 1:1 result looks like though a viewfinder with a true macro lens attached because my local photographic equipment retailers do not stock the lenses I am interested in to try on my camera body,therefore I cannot compare the filter against the true macro lens.

Keith

[Dave Humphries]

Hi Keith,

It's a shame you're quite so far away, I have recently acquired a couple of old AI-S ones myself and we could have met and you could try them; one does 1:2, the other I think does 1:1, only just discovered that one (long story).

I don't have close up lenses, so the pair of us are mutually useless neither one has experience of the other's situation!

Don't suppose you're coming 'down south' soon?

[Keith]

Hi Keith,

It's a shame you're quite so far away, I have recently acquired a couple of old AI-S ones myself and we could have met and you could try them; one does 1:2, the other I think does 1:1, only just discovered that one (long story).

I don't have close up lenses, so the pair of us are mutually useless neither one has experience of the other's situation!

Don't suppose you're coming 'down south' soon?

I'm afarid not Dave, but thanks for the offer.
I was just hoping someone may have used both.

I have just discovered that if I took a photo of a square approx 4 1/4 inch x 2 3/4inch at 200mm at a given distance it should fill the frame, therefore if I attach a close up filter and it records 1/4 of it at the same given distance then I assume it is 1:1.
Well thats about as genius as my brain gets at maths so I am probably way out,lol.

[BeardyGit]

Dumb idea: take a picture of a ruler. If you can see 36mm x 24mm then you've got a 1:1 ratio (at least with full frame). Can it be that simple?

I will admit that I'm confused by what lens vendors mean by magnification factors on crop-fram sensors.

[Keith]

Dumb idea: take a picture of a ruler. If you can see 36mm x 24mm then you've got a 1:1 ratio (at least with full frame). Can it be that simple?

I will admit that I'm confused by what lens vendors mean by magnification factors on crop-fram sensors.

I can see where you are coming from Beardygit (great name by the way), I guess I would have to subtract 25% from those dimensions for a cropped sensor.
I would imagine other factors come into the equation such as focusing distance and close up filter magnification rating.