Atmospherics!

[Uncle Kevriano]

I thought it may be useful to some, to illustrate how much heat haze can completely knacker your photos and that there is nothing you can do! This shot of a rare visiting Black Winged Stilt was taken mid afternoon yesterday (it hadn't showed early when there was less haze) and though it was only 40 yards away, the heat haze has completely destroyed any hope of it being sharp, or even look like it's in focus. If you weren't aware of this phenomenon you could be forgiven for thinking that there was a problem with the A7RIV or 200 600 or both, but no, close shots of other subjects in the same conditions are fine. It really can be soul destroying (it is!), but this is a useful illustration I think.
Back up there early tomorrow. Hope they are still around!

• ILCE-7RM4
• FE 200-600mm F5.6-6.3 G OSS
• 600.0 mm
• ƒ/7.1
• 1/1250 sec
• ISO 640

 

[MrFotoFool]

Good illustration. That is one of the arguments against spending a fortune on a supertelephoto lens like 800mm or 1200mm; it's hard to avoid atmospheric distortion at those distances.

Steve Perry (good Nikon instructor) found an interesting phenomenon related to this in extremely cold weather. If the telephoto lens is in a semi-warm car and you go out and shoot when it is below freezing, the warm lens hood causes heat distortion and the only way to get a clear image is to take the lens hood off.

 

[Uncle Kevriano]

Good illustration. That is one of the arguments against spending a fortune on a supertelephoto lens like 800mm or 1200mm; it's hard to avoid atmospheric distortion at those distances.

Steve Perry (good Nikon instructor) found an interesting phenomenon related to this in extremely cold weather. If the telephoto lens is in a semi-warm car and you go out and shoot when it is below freezing, the warm lens hood causes heat distortion and the only way to get a clear image is to take the lens hood off.

Yes, we've had some discussion on that here. It really only applies f you are going quickly from indoor to outdoor, and more so in cold climates. but it is a thing.

 

[Jeff A]

The phenomenon is actually referred to as Mirage. Long range rifle shooter battle this a great deal. Until recently, I was a long range rifle competitor. The competitions are held at 600 & 1000 yards. Atmospheric conditions make it very difficult and is complicated by having an Optic mounted over a very hot barrel.

 

[Uncle Kevriano]

The phenomenon is actually referred to as Mirage. Long range rifle shooter battle this a great deal. Until recently, I was a long range rifle competitor. The competitions are held at 600 & 1000 yards. Atmospheric conditions make it very difficult and is complicated by having an Optic mounted over a very hot barrel.

Good comparison, and actually an apt term for it too. I have other words I use

 

[krisljungberg]

Is it just me or is it even harder on a sunny day when water is involved as well? The reflections and all that. Even if the subject is closer than that it can be tricky to get sharp images.

 

[Uncle Kevriano]

Is it just me or is it even harder on a sunny day when water is involved as well? The reflections and all that. Even if the subject is closer than that it can be tricky to get sharp images.

Absolutely, and if you look past the bird in this shot it really shows it well, the "mirage" effect is very evident. I couldn't avoid the sun on this day, as I had to go for the birds in case they don't stay. It's cloudy here today, and they are still present. I may get back.

 

[krisljungberg]

Absolutely, and if you look past the bird in this shot it really shows it well, the "mirage" effect is very evident. I couldn't avoid the sun on this day, as I had to go for the birds in case they don't stay. It's cloudy here today, and they are still present. I may get back.

Yeah I have a lot of "evidence photos" of birds. They look like sh*t but you know what species they are at least, so they count towards the list! ;D

I think another widely used term for this is "heat distortion".

 

[FowlersFreeTime]

So many factors involved. Mirage is usually applied when it's heat, but when dealing with long distances dust and haze can be present without heat. Most just refer to it as atmosphere. This example shot was posted in another thread. It was a test shot for a lens and TC I bought. The bridge railing in the photo is over 1800', or a third of a mile away. Even though there's no heat mirage evident, the image is still degraded in clarity with a foggy look in the distance, along with loss of contrast. I know this isn't due to the lens and TC combination because it performs very well under normal shooting distances.

DSC00386 by telecast, on Flickr

So this is interesting because some reviewers of the Tamron 18-300mm for APSC (27-450mm full frame equivalent) do not mention atmospheric conditions, but derided the lens for being soft on the telephoto end of things. It could just be that those youtubers don't know the physics that contributed to their less-than-sharp shots at 300mm. To be honest, neither did I until I found this thread. I learned something new today, thanks all.

 

[Blake81]

I noticed this same condition while photographing Bald Eagles this past weekend. I was taking photos around 11am and the heat really did a number on the sharpness.

 

[Jeff A]

Good comparison, and actually an apt term for it too. I have other words I use

When shooting a rifle at 1000 yards, I would just prefix the word with a 7 letter adjective.

 

[Deleted Member 5003]

If your only use for a telephoto is to bring distant objects closer, then you're missing half the boat. While it's become common for us to think of it them that way and is usually the first thing someone says when asked "Why buy a telephoto?", it really isn't the main purpose.

Yes, we all do it, I stand guilty as charged. Sometimes there's no choice, like at an air show. But the best use of a long FL is for composition. The simplest way to illustrate this is to take a photo of something from a normal, reasonable distance. Since this place is bird heavy, I'll use the example of a small bird on a fence 20' away using a standard 50mm lens, and then the same shot of the same bird from the same distance using a 600. You didn't move, you're still 20' away, and even though it looks like you were closer all you did was fill the frame with the subject using a telephoto lens.

Personally, I buy the longest lens I can lay my hands on without taking out a second mortgage on the house. I love them, I have no idea how anyone can get by without one. My next planned purchase is a 2X TC for the 200-600.

I think reach is being confused with compression, wouldn't recommend a 2x convertor however in my experience with nikon and Sony lenses a 2x always gives appreciably softer images.. The 1.4x however with one stop of light reduction will have limited impact on the quality of your images and focus speed. the 2 x will have a major negative effect in my experience. If you are planning in taking your long end out to an effective 1200mm and +f11.0 mirage/heat haze will definately potentially impact your images and have a major impact on focus speed(unless you will only shoot static objects)............?

I find shooting at the long end of my 200-600mm and implementing ASC from a programmed button on my A1 to an effective 900mm focal length is good for most situations and even with a 1.4 times convertor fitted to raise the effective focal length to 1260 mm yields all the benefits of a workable focus speed and image filling the frame, mirage /heat haze however will always be a threat............food for thought...?

 

[Deleted Member 5003]

Thanks. While your statement is generally true, there are more than enough image samples out there that show your assertion in regard to the 200-600/2X to be incorrect. They play very well together.

I'm not a fan of APS-C mode. It's digital cropping, that's it and that's all. You can just shoot the image in FF then crop to whatever 'zoom' you want, and in many cases it will be less than the crop applied by APS-C mode. I have APS-C programmed to my focus hold button because I never use focus hold. If I need to recompse after focusing it's easy enough to just keep the shutter button at half-press. I can press the FH button to temporarily zoom in to check composition or some detail, but rarely use it to take a photo. It makes no difference if you're cropping in the camera with APS-C or in post, removing pixels is removing pixels.

I respect your opinion, but the balance of professionals would not concur for high quality image creation or processing.

On pixels cropping i agree, ASC cropping whether in camera or in post processing amounts to the same thing and it all depends on the camera you have being a high resolution body or otherwise, you didn't mention which camera you are using........ Personally with my A1 I can crop 200 % in post processing and still create high resolution images for large scale print out or otherwise. At low resolution I agree the challenges are different.

 

[pointreyes]

So this is interesting because some reviewers of the Tamron 18-300mm for APSC (27-450mm full frame equivalent) do not mention atmospheric conditions, but derided the lens for being soft on the telephoto end of things. It could just be that those youtubers don't know the physics that contributed to their less-than-sharp shots at 300mm. To be honest, neither did I until I found this thread. I learned something new today, thanks all.

Not in my case. Tested at only 50 feet on a bright clear sunny day at 1/800 of second and still too soft for my taste. I also tested the lens with an infrared converted camera which does cut through haze ( https://www.lifepixel.com/photo-tutorials/infrared-haze-reduction ) and it was considerably worst than any of my other lenses that I have used. I expect IR images to be a little soft due to the way the light wavelengths are recorded on the sensor but the lack of sharpness was some of the worst I have ever experienced. I'm pretty sure I had a bad copy.

As for APSC mode on a full frame camera: I love it. I sometimes need that extra reach for an event and until I go into crop mode I may not have eye AF kick in.