What does magnification ability mean in the reviews?

[nathansym]

I have been reading the lens reviews and they will say something like "Combining a long minimum focusing distance (4.9') with a high focal
length, the Canon EF 100-300mm f/4.5-5.6 USM Lens turns in a mediocre
.2x magnification ability."





Can someone explain what .2x magnification ability means?


Obviously the lens magnifies the subject more than .2x





Thank you in advance.

[Brendan7]

I don't know too much about the technical aspect of photography, but I believe the statistic means how large the real-life object is magnified on the camera's sensor. .2x means that an object is shown at 20% of real size on the sensor at MFD. (somebody correct me if I'm wrong).


brendan

[nathansym]

Does MFD = Multi Function Display?





I guess I know even less because I am not sure what impact of that is?


If I have a zoom lens that magnifies the image 10x and and the sensor but it only has .2x magnification ability, what does that mean?





I tried googling "magnification ability", "magnification ability lens", "magnification ability lens photography", but I cannot find any good resources.

[Sheiky]

Hey there,


MFD means Minimum Focus Distance, or with other words the closest distance you can focus on with that type of lens.


The magnification number as you say is easily understandable by looking at what 1X magnification means. 1x magnification means that the image on your camera's sensor matches the proportions of the subject in the image(the real life proportions). For instance if you shoot a 1 inch long nail at 1x magnification, the nail will be 1 inch long on your sensor.


The other thing you mentioned is totally different. You mentioned zoom. When you have a lens, let's say the canon 100-400 L, the zoom you have is 4x since 400mm is 4x 100mm. It has nothing to do with magnification though.


Hope this clears a bit!


Jan

[nathansym]

So would you say, in general, the magnification is related to the MDF?


Meaning the longer the MDF, the lower the magnification.





I know there are macro lenses lenses with different MDFs that still have 1:1, and I assume it has to do with the optics but is that a good rule?

[nathansym]

And I meant MFD not MDF.

[Brendan7]

So would you say, in general, the magnification is related to the MDF?


Meaning the longer the MDF, the lower the magnification.





I know there are macro lenses lenses with different MDFs that still have 1:1, and I assume it has to do with the optics but is that a good rule?

Somewhat. Some lenses can focus at 12'' but because they are 50mm lenses the Magnification is low. Macro Lenses (100mm, 180mm) combine a long focal length and short MFD to magnify a small subject at 1:1. Focal length plays a part too! My 300 f/4L IS focuses at 5' but because of its focal length it gives a decent .25x magnification.


Where's Daniel Browning when we need him!? [:P]


brendan

[neuroanatomist]

Meaning the longer the MDF, the lower the magnification.

At the same focal length, yes. But, for example, the 300mm f/2.8L and the 400mm f/5.6L have almost the same magnification (0.13x/0.12x), however, the MFD for the 400mm is 3 feet longer than for the 300mm f/2.8. Then there's the 300mm f/4L, which has an MFD that's much shorter than the 300 f/2.8, and thus a magnification of 0.24x. These values are a function of lens design and vary from lens to lens. The best way to find them is to check Bryan'sLens Specifications and Measurementspages.


Also, teleconverters affect the apparent focal length but not the MFD, so they actually increase maximum magnification (e.g. the 0.24x mag of the 300mm f/4 becomes 0.34x with a 1.4x extender).