Magnification and zoom vs. macro

[Bebop]

I have recently been enjoying taking photographs of butterflies with my 70-300mm IS lens. On the computer I then have to crop massively to 'magnify' the butterfly. I am just wondering whether I need a larger zoom or a macro lens so that my butterflies fill more of my image.

I have done some reading on here, but I haven't quite been able to fathom whether a macro lens will help me as I am rarely so close that I can't focus. (Might need to improve my field skills!)

I assume that I would only get the 1:1 magnification of a macro lens if the subject was at the minimum focussing distance? Can anyone tell me is this correct? I can't quite get my head round it.

At this point in time I'm not interested in real close ups of insects etc…. not yet anyway

 

[StewartR]

A conventional macro lens such as the Canon 100mm f/2.8 will give you 1:1 magnification at the minimum focussing distance, which for this lens is 31cm. 1:1 means that you can fill the frame with an object the same size as the sensor, i.e. 36x24mm for a 5D-series camera. At distances greater than the MFD, the magnification will be less so you'll need a larger object to fill the frame.

Remember the MFD is measured from the sensor, not the front of the lens. So 31cm is pretty close!

 

[Bebop]

Thanks Stewart that's what I thought… so in fact a macro won't help me unless I can sneak up on them and get nice and close.

Canon make a 100mm with MFD of 30cm and a 180mm with a MFD of 48cm, both with 1:1, so in fact I'd only gain an extra 18cm to get full magnification and I'd lose the IS of the 100mm…. hmmm interesting.

I do have a 5dIII. Maybe I will have to hire a lens and try it out!!

I'd like to do more bird photography, which is why I was wondering about a bigger zoom too, but then the MFD gets even greater…. decisions, decisions...

 

[StewartR]

Mmmm, it's not easy.

Here is a chart of the detailed specifications, including MFD and maximum magnification, of virtually all Canon's lenses. It's a couple of years old now so it doesn't show some of the very newest ones, but it's the most comprehensive source I've come across. Some of the MFD and magnification figures make interesting reading. For example the 300mm f/4 L IS USM has a MFD of 1.5m, at which it delivers a magnification of 0.24x which is relatively high. Stick a 1.4x or 2x Extender on it and you have a magnification of 0.36x or 0.48x at the same MFD; that sounds like it could be quite handy for butterflies. With your 5D III you'd still have AF even with the 2x Extender giving you 600mm f/8. Shutter speeds might be a bit slow but your camera can easily cope with the ISO being bumped up to compensate. Just a thought.

 

[Bebop]

That is a great chart, thank you… I had thought about a 400mm prime, but it has a huge MFD. I do already have a 70-200 f/2.8 which would take an extender, but it is so heavy and I don't need the f/2.8 (for butterflies) Funnily enough I nearly sold my 70-300 when I got this, but I'm so glad I didn't! The 300mm f/4 would be lighter and I do always tend to use the 70-300 at 300.

I have been shooting butterflies at f/11 or even smaller apertures to try and get as much as possible in focus so f/8 is not a problem, and yes the ISO capability of the 5DIII is a huge plus.

i shall print the chart off tomorrow and highlight the important ones so I can compare them more easily.

Thank you for your help!

 

[moaten]

for the 300f4 + you can also use extension tubes to get closer to the subject for maco

 

[petersmart]

for the 300f4 + you can also use extension tubes to get closer to the subject for maco

You can use extension tubes on your 70-300mm lens and get great close ups while still being a good distance away.

The technique seems a little odd at first (or it did for me) because it's easier to focus with the zoom rather than the focus ring, but you can soon get used to it.

And I also use Manual focusing moving back and forth to get the subject in focus as the DOF is quite small as it is with all macro photography. and usually use from f16 in bright sunlight.

I use this technique quite a lot coupled with a Jessops 320AF flashgun.

The flash is tall so even though the lens and tube arrangement is quite long I don't get shadows cast on the subjects (with a bit of care).

These pics were taken with that arrangement but no flash:

​

I have Kenko tubes but you can get Polariod auto extension tubes for about £60 on Amazon.

And the advantage of extension tubes is that you can use them on any lens to act as a macro lens.

.

 

[Bebop]

hmmm interesting - another option! Thanks for the suggestion - as you can see I know nothing about macro I had thought extension tubes were for real close ups of flowers and insects rather than things a bit further away like butterflies. I recently turned down some 2nd hand ones offered to me too :bang:

Today I took some more butterfly photographs and I was able to get closer than my MFD several times, so maybe my field skills are improving, or else they were all a bit dozy.

I've also just realised that the 24-105mm lens has quite a close MFD so I suppose I ought to give that a try before I jump in and make a mistake.

 

[woof woof]

I am just wondering whether I need a larger zoom or a macro lens so that my butterflies fill more of my image.

I think it's worth thinking carefully about what you want to achieve and how the image is going to be presented and viewed.

If you want a big print you're going to want to fill the frame as much as possible and that'll probably mean getting close and probably using a macro lens like a 150mm.

If on the other hand you only want a small print or perhaps don't print at all and only want to fill your screen then you'll probably get away with a quite ordinary lens and heavy cropping.

For example, I took this picture with my G1 and a quite ordinary 50mm. On FF a lens of about 100mm would give about the same FoV.



I cropped it so that it fills my computer screen and it looks very detailed.



So, if you want to print big you'll need a longish macro but if you only want to fill your screen almost any longish lens will probably be fine.

 

[Bebop]

I think it's worth thinking carefully about what you want to achieve and how the image is going to be presented and viewed.

If you want a big print you're going to want to fill the frame as much as possible and that'll probably mean getting close and probably using a macro lens like a 150mm.

If on the other hand you only want a small print or perhaps don't print at all and only want to fill your screen then you'll probably get away with a quite ordinary lens and heavy cropping.

So, if you want to print big you'll need a longish macro but if you only want to fill your screen almost any longish lens will probably be fine.

Thank you Alan. Yes, that's exactly my dilemma. So far I have been cropping away and just viewing on screen, but I am thinking I might like to print some off. I'm also aware that this is my first year of shooting butterflies and at the moment I still feel like a child in a sweet shop Perhaps I should hold off for the moment. I may also become better at creeping up on them in time.

This is the sort of crop I'm having to do