Heat haze

[GYRob]

just a genral question really.
im not into scoping but wondered if you guys suffer from heat haze i use a 500f4 thats around 10/12 times magnification and if i try to shoot at a long disdance it just hazey.
your scopes are far more powerfull so do you have the same problem.
Thanks
Rob.

[Neil]

Rob,
Yes , in spades. I usually don't bother digiscoping at distance after about 10.00 am , until about 4.00pm here in Hong Kong at this time of year . In summer it's much worse so 2 hours after sunrise and 2 hours before sunset is the go.
Neil.

[Barred Wobbler]

I'll vouch for that. This Dartford Warbler wasn't even distant, yet the late morning heat in north-east Spain softened the image at only about 15-20m. It's a full-frame image without cropping and after the unsharp mask, and still it's soft.

[GYRob]

Thank's guys i had wonderd about it as it can really mess dslr images up and we are no were near the power of your gear.
Rob

[Sout Fork]

im not into scoping but wondered if you guys suffer from heat haze

your scopes are far more powerfull so do you have the same problem.
Thanks
Rob.

Yes, Yes, Yes.

All that air between your subject and your optics is as much a part of your optics system as any lens. In my part of the world 300-400 feet is the limit for high quality pics as a rule. I have seen 500 feet of air reduce a $7000 Canon telephoto pic's to soft mush.

Following was taken early in the morning at about 300 feet and turned out much better than I expected. Pentax 100mm spotter at 38x

[GYRob]

Sout fork
Looks like your onto a winner with your set up when used as stated thats a rather nice shot.
Rob.

[Barred Wobbler]

Yes, Yes, Yes.

All that air between your subject and your optics is as much a part of your optics system as any lens. In my part of the world 300-400 feet is the limit for high quality pics as a rule. I have seen 500 feet of air reduce a $7000 Canon telephoto pic's to soft mush.

Following was taken early in the morning at about 300 feet and turned out much better than I expected. Pentax 100mm spotter at 38x


Another tip is to avoid "ground-grazing rays" and the refraction problems they bring. I was taught many years ago as a trainee surveyor that when doing survey work in sunny weather when the ground was warm to avoid any circumstances when the line of sight between the instrument and the target came within two feet of the ground, whether by avoiding reading below two feet on the measuring staff, or by avoiding situations where intervening ground bulged up into the no-go zone.

Difficult or impossible to put into practice when photographing ground-dwelling birds I know, but looking at photos I've taken in the past larks etc are much more affected by softness than a bird sitting on wires at a similar distance in similar atmospheric conditions. So if there is a lump of hot earth sticking up between you and a bird, move so that if possible the land profile is concave between you and your target. It doesn't even need to be high temperature. I had photos of a partridge at only moderate distance ruined by refraction in early March in England. It's the difference in temperature between the ground and the air immediately above it that is the problem. Hot ground/Warm air, Warm ground/Cold air can be equally as bad.

Or pray that the sun goes in. (I find the opposite is usually the case - I'm getting lined up on a distant raptor and the sun comes from behind a cloud and here comes the refraction again).

Incidentally, I was recently taking photos in strong sunlight at 10,000 feet up a mountain in Spain, and I found that the photos were much clearer than at sea level. Similarly in the Almeria desert last summer the dryness of the air helped immensely.

[Neil]

Alan,
Good advice. Thanks.
Neil

[GYRob]

yes intresting Alan some point to take on there .
Thanks
Rob.