Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

[Nathaniel]

I would like to know from the members who have the Kenko convertor whether one should switch off the IS on the lens or is it OK to leave it on.I have noticed a slight blur in the images when taking pictures of small birds at a distance and I am wondering whether this is caused by the IS not being turned off.

Many thanks

Nat

[Neilly]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Hi Nathaniel,

I would've thought the IS would help. Not sure what sort of shutter speed you're using but when using the big lens on birds I up the shutter speed, slightly.

Another point - which AF points are you using? I use centre spot or centre + assist. If the birds have a lot of background behind them, that may give a false focus point, if you're using multi point AF.

Cheers,
Neil

[GORDH]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

On my 70-300 Nat I 've never noticed ant blurring with the I.S there is a concensus of opinion that when mounted on a tripod using slow shutter speeds that the I.S should be turned off as its movement could render images blurred, as can the panning setting 2 but in all honesty I've never had a problem I suspect that the blur could be down to too low a shutter speed as its a longish lens and coupled with your 1.4 convertor making it 420mm with your 6D and 672mm (I think) on your crop body, plus longer and not as easy to handle...for you short people ...only kidding

What shutter speed were you using on these blurred images ?

[Nathaniel]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

HI! Neil and Gord, thanks for your comments. I always handhold & use a shutter speed that is slightly higher than the focal length of the lens. For example when I use my 55-250mm lens on the 100D I use a shutter speed of either 1/560 or usually 1/640. AV is auto and it goes to f8. I use centre point focus & use partial metering. I noticed this today when after about 1hr watching sand martins I saw them land on a piece of beach. I took two photos (before they flew off) with my 100D +55-250mm +1.4 kenko and thought they looked quite OK on the LCD screen. But when I downloaded them to my computer I was disappointed to see a slight blurr. I will post these images after I have edited the same as best as possible. I also have got these in RAW but I don't think I can make them sharp via DPP. Attached a 2 photos which are not edited. Posting the JPG images for your comments.

[JanHarper]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

I downloaded a PDF document from the EOS Magazine Shop that gives instructions for the Kenko Teleconverters and info for cameras and different lenses. The following quote is from page 1 of 4. "VR (Vibration Reduction) function may or may not work. To avoid problems with VR, turn this mode OFF."

[Nathaniel]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Thanks Janet. Much appreciated. I have not cropped the above two pictures as I find that they are not sharp when magnified on mycomputer; I always think of cropping if the image is sharp when magnified.

[GORDH]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Difficult to see properly Nat as I cant zoom in but looking at the stones on the ground at the front they look sharper than the bird which could indicate out of focus due to af not being on the bird, how close were you to the birds I'm thinking minimum focus distance, also I would have used a higher shutter speed with the combo as can be difficult to hand hold for some that being said this doesnt look like blur to me well not camera shake either as the stones are sharp and at he shutter speed of over 500 you shouldnt have any problems with I.S on... so to sum up either af point not on the bird or shutter too slow

Edit...Managed to zoom in (not familiar with Photbucket Doh!!) and the stones in front of the bird are way sharper than anywhere else in the image so A.F definately not focused on the bird

[Nathaniel]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Many thanks Gord for taking the trouble. I posted the pics via photobucket as I did not wish to mess up my flickr site.I am sure you are right considering that I was rather quick to take the shot before the birds took off again. Yes, I do have fairly steady hands. I may have been about 25yds away from the birds but inside a hide. Hope I will have better luck next time; I will switch off IS as well just to make certain.

[GORDH]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

So you were well outside the minimum focussing distance of around 4ft, the bird could be blurred due to movement as 500-600th aint that fast with birds, even bobbing their head can be blurred at that speed but usually theres a ghosting effect which makes me think its to do with the A.F point not been on the bird, like I said the bottom of the image is sharper on the stones than the bird so I'd look at the focus point in DPP first

[antoeknee]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

If as Gordon says the focus is not on the birds it might be worth doing a big of testing with IS on and off.

On a side note the birds are house martins and not sand martins.

[Nathaniel]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Thanks Ant and Gord (for further comments). Yes, I have looked at the focus point on DPP (RAW image) and yes, the focus had fallen on the stones. I must look at my 100D manual and also David Taylor's guide to see whether it is possible to bring into play ALL the focus points. This was possible with the older DSLR where I remember that there was one control via the mode dial which would bring all the focus points into play. I think this has disappeared with the more modern DSLR's- or am I mistaken here?

Thanks Ant for your ID. There were plenty of these little birds yesterday, flying this way and that way.

[antoeknee]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

For this subject would definitely select either centre only or centre plus assist. If the bird was centre of the frame and focus was on focus on rocks in foreground sounds like all AF points are being used.

Re ID worth taking a look at your guide. Sand Martin is mainly Brown with white/cream under parts. House Martin similar size but dark blue (like swallow) with white underparts. One easy identification clue for house martins is the white rump, the bit where wings finish and tail starts. You'll easily spot this when they are flying.

[GORDH]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

If you set your camera up for back button focus Nat and disengage focussing on the shutter button you could then focus on the bird and recompose without it refocussing, as antoeknee says its possible that you already have all A.F points enabled which focuses on the nearest object, I would go with centre point only

[Nathaniel]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Thanks Ant and Gord. I generally set my TV and let AV be on auto, along with auto WB etc. Hence I could not have been using all AF points and via my RAW image the point of focus has unfortunately been on the rocks. Good point Ant re the ID.

[antoeknee]

Re: Should IS be switched off when using the Kenko HD DGX 1.4x teleconvertor

Err, choosing TV or AV doesn't choose AF points for you. You select them and then it stays the same whichever mode you select.