Do I need a wider aperture?

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I'm taking photographs of animals, mainly horses, sometimes in sports, so obviously I need a fast shutter speed. But I'm finding that even at ISO 3200, I often can't get a better shutter speed than 1/100 in the barn during the day.

I noticed that Olympus have 90mm and 150mm, 35mm equivalent f1.8 lenses, would these be the solution to my problem?

http://www.olympus.co.uk/consumer/pen-camera_pen_21693_21730.htm

 

[Energize]

The lens I have at the moment has a maximum aperture of 3.5

 

[Energize]

Is this a fixed aperture lens or is is a variable aperture zoom (e.g., it might be f/3.5 at the wide end and f5.6 at the long end).

It's 3.5 at 28mm and 5.6 at 84mm.

I was concerned about dof, but the only other option seems to be getting a body with a bigger sensor.

 

[Energize]

> a bigger sensor.

Which will also reduce your depth of field. What you really need is more light. I wouldn't suggest you use flash with nervy beasts like horses but a couple of portable spots might be worth considering.

Flash doesn't bother them, but the arena is too large for the built in flash to have any effect.

 

[Energize]

Secondly, if your framing the whole horse then you have much more DOF as your either further away, or using a wider lens, whichever it is the important thing to remember is the wider the view, the more DOF you have.
Also as your using a smaller sensor, your closer to the hyper-focal point, so DOF should be even less of an issue.

I'll typically be framing the whole horse for the fast moving sports pictures, the shots will be 20-30m away, what focal length lens would you recommend?

 

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On crop boy a 70-200mm f/2.8 would be ideal, Zooms are invaluable in such situations and give you flexibility in choosing closer crops of the head or fuller body shots. But it doesn't look like there is an equivalent for m43s?

Possibly but 4/3 lenses are compatible with m4/3 cameras maybe there are some options there?

Otherwise the 150mm equivalent @ f/1.8 sounds good. When light levels are really critical but some reach is needed then the go to lens on FF/crop is a 200mm f/2.0 , so 150mm equivalent @ f/1.8 is similar.

One thing to consider is AF speed. Often the fast wide aperture primes have a slower AF due to the need for more accurate focusing when used wide open. E.g the Nikon 85mm f/1.4 is much slower than the 70-200mm f/2.8.
Definitely research what these lenses are like for fast action.

Not sure how important auto focus is for showjumping? The jumps can be focused in advanced.

Lastly, the sensors in m43s cameras are definitely behind the times in noise performance. Although going to a larger sensor will give its own problems (you get less reach so will need longer lenses, which will be more expensive and heavy for the same aperture, you will also get a shallower DoF so may need to stop down more, reducing the light gathering potential). However, the sensors in new crop and FF cameras are significantly better such that ISO 3200 is perfectly respectable and on the newest FF sensors you can push ISO 6400 at least. Before investing in expensive glass for m43 perhaps consider what type of photography you are really interested in and whether it is worth upgrading to a full DSLR.
m43s don't compete in the same ball park for high ISO performance AND auto-focus speeds and reliability AND high-speed action photography in general (their forte is street, casual, trekking/exploration, some landscape work and due to effective reach can be OK for wildlife, good for safaris etc.). They definitely are not good for indoor/dark sports-action.

I say this because I doubt that Olympus 75mm f/1.8 is cheap so worth considered all options before departing with lots of cash.

45mm 1.8 is ~£200, 75mm is an extortionate £700! I will look intro renting lenses or an slr camera when I need to film these more demanding events if necessary.

 

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Actually works out considerably cheaper to sell my camera and buy a Canon 1100D body and f1.8 prime lens. Can't believe the extortionate cost of m4/3 lenses, no wonder they are not popular.