Lens recommendations

[Dave McCormick]

I have Sigma 105mm EX DG Macro which I have used on Canon cameras for 3 years (400D, 500D and 600D) and although its shorter than the 150mm, its quite sharp and never had an issue with it, only issue was that auto focus was slow in some instances, but manual focus is quite fast and I prefer it over manual focus 99% of the time. Couple of photos taken with it:

Small Tortoiseshell (Canon 400D, f/5.6, 1/500sec, ISO-400, Pattern Metering, No Flash, Handheld):

Small Tort

Scorched Wing (Canon 500D, f/10, 1/100sec, ISO-400, Pattern Metering, No Flash, Handheld):

Scorched Wing

Silverweed with Sea Milkwort around it (Canon 400D, f/13, 1/320sec, ISO-400, Pattern Metering, No Flash, Handheld):

Silverweed

I have the Tamron 18-200mm IF Macro which I got as part of a kit with my 500D and I would not recommend this lens to anyone, quality gets bad farther you zoom in, fully zoomed out the picture quality is OK but the Canon 18-55mm lens can give better quality. I have only used it a small number of times and have not used it since. Back in August last year I was passing my garden coming home and saw a male large white trying to pair with a female which didn't want it. Since I only had the Tamron lens on my camera at the time, I shot this (couldn't get close enough) and its not great, best I could do:

Normal (Canon 500D, f/8, 1/200 sec, ISO-200, Partial metering at 200mm zoom, No Flash, Handheld):

Large whites

Cropped:

Large whites Cropped

I also have the Canon EF 50 mm F/1.8 Macro lens. Its good for a cheap macro, but it is let down by the fact you can't really make good use of the f/1.8 because the min focus distance is 1.5ft. I don't have many photos I took with it, but the videos I took with my 600D with it came out sharp enough but don't have photos to show with it at moment. I probably wouldn't recommend it for butterflies though, for plants (getting whole plant in the shot) its fine enough and for nothing too small that you need to get closer than 1.5ft to get a good shot from.

[Rogerdodge]

Dave
I am not sure I understand what you mean by this-

....but it is let down by the fact you can't really make good use of the f/1.8 because the min focus distance is 1.5ft.

Can you clarify?
Cheers

[Dave McCormick]

Dave
I am not sure I understand what you mean by this-

....but it is let down by the fact you can't really make good use of the f/1.8 because the min focus distance is 1.5ft.

Can you clarify?
Cheers

What I meant was that you can't get close enough to a subject to make good use of a f/1.8, not really useful shooting a subject at f1.8 if your not close enough to it and I didn't think 1.5ft was close enough. I have not figured out anyway how to get a good shot of a subject at f/1.8 yet.

[dilettante]

What I meant was that you can't get close enough to a subject to make good use of a f/1.8, not really useful shooting a subject at f1.8 if your not close enough to it and I didn't think 1.5ft was close enough. I have not figured out anyway how to get a good shot of a subject at f/1.8 yet.

I wouldn't think there'd be many occasions where you'd want f/1.8 for a macro or close-up shot, would there? The depth of field would be so shallow as to be unusable in most cases.

f/1.8 is more useful for portraits and the like, but then you're going to be more than 1.5ft away at 50mm focal length.

[Gruditch]

Hi Dave, I think your find the Canon EF 50 mm F/1.8, isn't a macro lens.

Regards Gruditch

Edit, Damn it dilettante, you beat me to it.

[Dave McCormick]

Thanks dilettante and Gruditch, it was actually the EF 50mm f/1.8 II lens. Not sure why I said macro. I was just thinking to use a f/1.8 properly, you'd need a small subject as I always thought that the smaller the f-stop number, the smaller the subject you could get in focus. Anyway, have to test it more to see since as I said, have not used it much yet but I suppose for portraits a f-stop like that would be good.

[Rogerdodge]

Dave
I think you may have a misunderstanding of apertures (f numbers).
Perhaps this short article will help.
http://www.photonhead.com/beginners/shu ... erture.php
Cheers

[MikeOxon]

Dave,

I hope Roger's suggested article helps. It is all a bit confusing!

A small aperture number actually means that the lens has a large opening! The number is actually the focal length divided by the diameter of the opening, so a 50mm f/1.8 lens has a diameter of 50/1.8 = 28mm. The size of the opening affects how much light reaches the sensor but it also affects the range of distances over which an object remains in focus. I think this last point is where your confusion has arisen.

For example, if you set the focus of a 50mm f/1.8 lens to 10 feet, objects between 9.6 and 10.4 feet will be in focus - a small distance of 0.8 feet. If you close the aperture down to f/16 and again set the focus to 10 feet, objects between 7.3 and 15.7 feet will be in focus - a much larger range of 8.4 feet! It isn't the size of the object which matters but how far it extends towards and away from the lens. You can use a large opening to make the background go blurred when you focus on a close subject or, as Padfield does in many of his shots, select a small opening (large aperture number) to show a butterfly within its surroundings.

There is another effect if you make the opening too small - say f/22 - which makes everything get a bit fuzzy. This effect is known as diffraction.

I hope that helps - try taking some photos with different aperture settings to see the effect for yourself.

Mike