# Thread: When macro lens say 1:1 and min focus distance, does it mean

1. ## When macro lens say 1:1 and min focus distance, does it mean

subject to sensor distance of 30cm? Or the front element of the lens to subject?

2. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Originally Posted by dRebelXT
subject to sensor distance of 30cm? Or the front element of the lens to subject?
The distance is usually the subject to the film/sensor plane.

3. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Originally Posted by lsisaxon
The distance is usually the subject to the film/sensor plane.
I believe so.

Regards,
Arto.

4. ## Re: When macro lens say 1:1 and min focus distance, does it mean

1:1 magnification meaning you will get sensor size full frame.

Focusing distance = distance between the sensor to the object

Working distance = distance between front tip of the lens to the object

5. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Originally Posted by megaweb
1:1 magnification meaning you will get sensor size full frame.
Unless I misunderstand what you're saying this statement is incorrect. 1:1 has nothing to do with sensor size. What it means is that when the lens is in macro setting for 1:1 and the subject is in focus. the size of the subject on the final 100% print will be the same as the original - e.g. you take a picture of a coin at 1:1 and then print the image at 100%, the image of the coin in the picture will be exactly the same size as the actual coin, i.e. life size.

6. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Ok, after reading up, is my understanding correct:

The 90mm lens achieve 1:1 at closest focusing distance of 30cm(sensor/film to subject), however the lens extend by 9cm and the un-extended lens is 11cm(measure from sensor/film plane). As a result, the lens front is 10cm from subject.

Assume on a 35mm film.

7. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Sounds cheem. But if u want to go extreme, get the MP-E 65mm f/2.8 Macro Photo.

8. ## Re: When macro lens say 1:1 and min focus distance, does it mean

Originally Posted by cyber_m0nkey
Unless I misunderstand what you're saying this statement is incorrect. 1:1 has nothing to do with sensor size. What it means is that when the lens is in macro setting for 1:1 and the subject is in focus. the size of the subject on the final 100% print will be the same as the original - e.g. you take a picture of a coin at 1:1 and then print the image at 100%, the image of the coin in the picture will be exactly the same size as the actual coin, i.e. life size.
You are right that it has nothing to do with sensor size. It also has nothing to do with print size. The 100% (or 1:1) refers to the size of the image at the sensor plane.

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