70-300 DO Tips and Tricks

[Fovea]

After about two years with this lens, I though I would share these Tips and Tricks.

Your feedback will be welcome.

Xavier.

[digitaldog]

Great piece, thanks. I'm somewhat new to this lens (I really like it) but picked up a lot of good tips from your article.

[Gregory]

one of your 'tips' is rather disturbing.

you observed that the DOF was narrowed (shorter) than for other equivalent non-DO lenses.

could someone else confirm this?

I shoot a lot of bird and (small) animal photos, and my DOF is already incredibly short. it's really difficult to get enough light and enough DOF. if I were to buy a 400 DO and have extremely short DOFs, I'd be very disturbed.

regards,
Gregory

[Fovea]

one of your 'tips' is rather disturbing.
you observed that the DOF was narrowed (shorter) than for other equivalent non-DO lenses.

What I am saying, is that for a 100% crop which is equivalent to a 60 x 90 cm (24 x 36 inches) image at 96 dpi (with any lens) shot at 2.5 m (8 feet), I consider a depth of field of about 5 mm (1/5 inch)...

I just used a 0,006 mm cercle of confusion instead of the usual 0,018 mm value for a 1.6 crop camera to take into account the larger print looked from very near.

Considering bokeh, I have made a few tests :
- overall bokeh appearance is not changed,
- there is a small bokeh texture difference near the focus point, but I do not have the equipment to really make a rule out of it.

Xavier.

[Gregory]

I could be mistaken, but I'm 90% positive that you had one extra 'tip' on your page which isn't there now, one which showed the difference in DOF in a photo between the 70-300 full open and another similar non-DO lense. there was a very obvious difference in the DOF.

regards,
Gregory

[Fovea]

I could be mistaken, but I'm 90% positive that you had one extra 'tip' on your page which isn't there now, one which showed the difference in DOF in a photo between the 70-300 full open and another similar non-DO lense. there was a very obvious difference in the DOF.
[a href=\"index.php?act=findpost&pid=79399\"][{POST_SNAPBACK}][/a]

This was tested with a 17-85 mm lens from a friend at 70 mm. There was a reproductible perceived difference around the focus point indeed (I was showing a crop). But no significant difference in overall bokeh though.

I then borrowed a 70-210 mm lens, and I couldn't reproduce it as clearly. Furthermore, at 200 mm there was no noticeable difference.

I guess it may be lens related bokeh differences and that is why I removed the tip. I consider that I do not have the equipment to test this more thoroughly.

Xavier.

[Gregory]

I guess it may be lens related bokeh differences and that is why I removed the tip. I consider that I do not have the equipment to test this more thoroughly.[a href=\"index.php?act=findpost&pid=79406\"][{POST_SNAPBACK}][/a]

understood. thank you for the explanation.

you're right though. 5mm is *very* short. I'm currently 'hunting' humming birds while visiting L.A., and my optimal distance from the birds with the 70-300DO at 300mm is just 4' so that the bird fills a nice portion of the picture. I'm trying as hard as hell to use f9 but it's sometimes not possible.

bird photography is not easy, but it's fulfilling when you get that one special photo ;-)