Lens tests - Canon 50mm, 100mm, kit, and Tamron 28-55

[tim]

I did some tests that people might find interesting. They were taking using the 300D using a tripod and mirror lock up, one shot on every F stop they can do, on high quality jpg. The photo is of the 100mm Macro box, under some natural light and some extra halogen lighting. I then imported them into photoshop, cropped them to be about the same size, used the auto-level function to make the whites more white and the blacks more black, and saved them as a high quality jpg (9/12). Click on the thumbnail to get to the 100% crop - each one's about 200kb, give or take.

The lens I used are (in order):

* Canon 50mm F1.8
* Canon 100mm F2.8 Macro
* Canon 300D Kit lens (EF-S 18-55mm)
* Tamron 28-75 F2.8

http://www.mrwild.co.nz/ExperimentalGallery/Tests/LensTests/index.html

[pcasciola]

Did you back away twice as far for the 100mm shots? If so, that is extremely impressive wide open performance out of the 100mm f/2.8 Macro. Surprising too that the Tamron is actually sharper than the 50mm at f/2.8. I did some tests and they were definitely too close to call, but in your test the Tamron is clearly sharper than the 50mm at f/2.8.

Thanks for sharing.

[tim]

Yep, the lenses were positioned so approximately the same image was in the viewfinder, so the 100mm lens was further back than the 50mm. For the zooms I put them approximately in the middle of their range - the precise values are below the photos in the exif info.

I didn't actually compare them myself yet... I was hoping someone would do the analysis for me ;) Feeling very lazy today :)

[dhbailey]

What sort of analysis are you looking for? They seem fairly uniform in focus, the images all seem to have better color balance at smaller F-stops.

I think you have nicely proven that, at least under the conditions of your test, these lenses are all pretty equal and can be used interchangeably, based on your framing and depth-of-field considerations.

The 50mm and 55mm show softer focus at wider f-stops, so that might be a consideration in selecting a lens, depending on lighting conditions. There may well be times when you need to use the 50mm f1.8 in order to get a low-light shot without flash, despite the softer focus.

Such comparisons are interesting, but ultimately the decisions need to be made (I find) based on framing considerations and lighting considerations, sometimes on shutter-speed considerations if there is action involved, and only in rare situations (for me at least) can I bother thinking about the softer-focus/sharper-focus tendencies of a particular lens.

When I have the option, I use the Tamron 28-75 rather than the 50mm f1.8 or the 18-55mm kit lens, because I know it will be sharper through a larger range of zoom and f-stops. But quite often other considerations overrule the issue of focal quality.