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Olympus OM-D EM-5 Discussion

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rogerfry
rogerfry e2 Member 8506 forum postsrogerfry vcard United Kingdom
6 Oct 2012 - 11:17 AM

Gentlemen....This DoF argument is getting out of hand! Tongue

I think the confusion arises because Paul keeps using the example of a 50mm lens on both cameras, and the figures he quotes are correct. However, what we are really interested in -(or should be!)- is the DoF in a particular photograph.

Using his his figures for a 50mm lens at f4 on m4/3 we have a DoF of 1.45 ft. To take the same photograph using a full frame camera we would have to use a 100mm lens.

5D with 100mm lens @f4 @10 ft gives DoF of 0.74 ft
5D with 100mm lens @f8 @10 ft gives DoF of 1.46 ft

So, to get the same DoF in any given photograph you have got to open up by two stops on a m4/3 camera.

Unless you've got some pretty exotic m4/3 glass, you can never get the same shallow DoF as you would using a 2.8 lens on full frame. Sad

I hope that makes sense, and maybe puts an end to the "discussion", before tempers begin to fray. Tongue Tongue

Last Modified By rogerfry at 6 Oct 2012 - 11:27 AM
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6 Oct 2012 - 11:17 AM

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mdpontin
mdpontin  106016 forum posts Scotland
6 Oct 2012 - 11:22 AM

Thanks Roger! That's exactly what I wanted to understand but didn't express clearly enough. Thanks everybody.

And now, since it's a beautiful October morning, I think I'll take the E-M5 out for some field work. Wink

Last Modified By mdpontin at 6 Oct 2012 - 11:23 AM
Carabosse
Carabosse e2 Member 1139395 forum postsCarabosse vcard England269 Constructive Critique Points
6 Oct 2012 - 11:30 AM

That is exactly my understanding as well, Roger - and what I have tried to say without success! You double up both the focal length and the f-number to get the same DoF. As you have demonstrated:

DoF (and FoV) is the same when using 50mm/f4 on M4/3 as it is on FF using 100mm/f8.

It's actually that simple. Smile

And why there are f0.95 lenses for M4/3. They sound OTT, but actually give the same DOF as f1.9 lenses, of double the focal length, on full-frame.

Paul Morgan
Paul Morgan e2 Member 1315243 forum postsPaul Morgan vcard England6 Constructive Critique Points
6 Oct 2012 - 12:29 PM


Quote: It's actually that simple

Yes it really is that simple.

There`s was someone on here that argued that the lensbaby was more difficult to focus on a 5D than a camera with a crop sensor, due to the full frame having less depth of field.

He didn`t have a clue.

rogerfry
rogerfry e2 Member 8506 forum postsrogerfry vcard United Kingdom
6 Oct 2012 - 12:46 PM


Quote: Incidentally, the HLD-6 grip has arrived, along with the GS-4 grip strap. More excuses to get out and play with the E-M5. Smile

Would be interesting to hear how you get on with the grip strap. -(Presumably you lose the use of the function buttons on the grip unless you push them with your left thumb!). Tongue

Paul Morgan
Paul Morgan e2 Member 1315243 forum postsPaul Morgan vcard England6 Constructive Critique Points
6 Oct 2012 - 12:54 PM

You loose the use of the buttons on the portrait grip.

Plus its a pain if you want to split the grip and use the first bit on its own, there`s nothing to attach the strap to.

rogerfry
rogerfry e2 Member 8506 forum postsrogerfry vcard United Kingdom
6 Oct 2012 - 5:14 PM

Mainly for Denny! .........This is a re-post of the shot I put up (on page 147) where you said try increasing the contrast a little. Now re-worked and slightly cropped.....how does it look on your screen?

1-p9180346.jpg

strawman
strawman  1022006 forum posts United Kingdom16 Constructive Critique Points
6 Oct 2012 - 9:36 PM

Just a note re depth of field, your comments are correct where the subject is much further away than the focal length of the lens. If you get much closer, say real macro photography, the equations governing depth of field get much more complex and the rules of thumb's you are mentioning for gauging DoF change. Then a lot of other lens parameters become important.

But yes for reasonably far from the camera shots, stick 50mm lens on a m4/3 camera and a 35mm camera and the full frame camera has greater depth of field, but it will also have a wider angle of view. Alter the lens focal length on the full frame camera to get the same angle of view and the smaller sensor camera has greater depth of field for same viewing angle. Or walk closer Smile

Paul Morgan
Paul Morgan e2 Member 1315243 forum postsPaul Morgan vcard England6 Constructive Critique Points
6 Oct 2012 - 10:24 PM

I`ve found the lensbaby to be far more forgiving on a 5D, there`s far more dof to play with John Smile

strawman
strawman  1022006 forum posts United Kingdom16 Constructive Critique Points
6 Oct 2012 - 10:27 PM

As Cappa said you need to get closer Paul Wink

Paul Morgan
Paul Morgan e2 Member 1315243 forum postsPaul Morgan vcard England6 Constructive Critique Points
6 Oct 2012 - 10:36 PM

I`ve done a far bit of martial art stuff from about three feet, good enough Smile

mdpontin
mdpontin  106016 forum posts Scotland
7 Oct 2012 - 5:50 PM


Quote: Would be interesting to hear how you get on with the grip strap. -(Presumably you lose the use of the function buttons on the grip unless you push them with your left thumb!).Tongue

I'm just back from a walk with the E-M5 in hand, using the 75-300 lens, the HLD-6 and the GS-4 grip strap. The jury is still out on the grip strap, mostly because it may prove to be a nuisance having to detach it in order to remove the battery grip, in order to access the in-camera battery. Otherwise, it adds security to strolling along camera in hand, as does the larger grip depth provided by the HLD-6.

The grip strap doesn't appear to lose access to any of the function buttons or dials as far as I can see. I was concerned that it would get in the way of the SD card door (I normally remove the card and load it into the card reader in my computer, rather than hook the camera up to the computer via USB), but it doesn't.

I'll continue with the current set-up and let you know of any problems, but on the whole I think it should work out well.

mdpontin
mdpontin  106016 forum posts Scotland
7 Oct 2012 - 7:06 PM

A sample photo from this afternoon's stroll near my home. This was using the Oly 75-300, and the E-M5 with the grip and grip strap:
1-full.jpg
...and a crop from the above at 100%...
1-detail.jpg
The fly's head isn't quite sharp - to be honest, I was focussing on the flowers, so...my fault. Still, I can't fault the camera/lens combination for handling, sharpness, contrast, etc. The only post-processing was to convert to a web colour space.

brian1208
brian1208 e2 Member 1110248 forum postsbrian1208 vcard United Kingdom12 Constructive Critique Points
7 Oct 2012 - 7:41 PM

Difficult to nail those flies some times isn't it Smile

I went walk-about on one of our local nature reserves this morning and reminded myself why I always use SAF + M. I spotted a male Stonechat at extreme range and had two goes at using SAF to get the shot but each time it was off, resulting in a soft shot. On my final go I used SAF to get approximately there then tweaked the final focus using the manual focus ring, getting this (which is the full crop of around 800 pix on the longest side The only PP is to reduce exposure a tad and add a small amount of sharpening

stonechat-mf.jpg

Last Modified By brian1208 at 7 Oct 2012 - 7:43 PM
mdpontin
mdpontin  106016 forum posts Scotland
7 Oct 2012 - 8:17 PM

A fine shot of a whinchat (?) Brian. One to be proud of. Smile

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