Lightning Shot Recommendations

[Manfred M]

Bill – The one general comment one can make about trends in lenses over the past 10 or 12 years is that while the optical quality has gone up with each successive generation, the mechanical quality has gone down. Metal parts have been replaced with plastics; and while there are many places that plastics can and do outperform metals, in many cases design decisions have been made solely to reduce costs. In many of these cases, the longevity and functionality of the product has been compromised. While this is quite understandable for consumer products, it does bother me when these changes creep into the high-end professional offerings.

I think there is plenty of evidence this lack of hard stop for the infinity setting is just a cost reduction move, and unless you are focusing manually, it is something most photographers will likely never notice.

Zoom lenses can be either parfocal or varifocal.
Parfocal means the zoom lens WILL keep focus in the same Plane of Sharp Focus as the Lens is zoomed.
Varifocal means the zoom lens WILL NOT keep focus in the same Plane of Sharp Focus as the Lens zooms.
I believe that it is fair to say that MOST zoom lenses are varifocal.

Your statement is absolutely correct for lenses for still cameras. Parfocal lenses are only important to video shooters when they are doing those nice and smooth zooms in and out, so this feature is found on video camera lenses.

The other feature that video shooters (as macro shooters) look for is a lack of focus breathing throughout the zoom range, as we don’t want the size of the image to change as we change focus in a scene[/QUOTE]

Therefore, for most zoom lenses the point of ‘infinity focus’ on the Focus Turret is actually slightly different, depending at what Focal Length the zoom is set. It would make VERY LITTLE (i.e. NONE) difference to the final image if the lens is actually focussed ‘at infinity’: but it is another viable yet very tiny reason we could suggest as to why zoom lenses, can focus past infinity.

I don’t think this comment is correct, as the infinity reference is a base reference for many lens design parameters and everything else is measured back from this point. As an example, the zoom lens focal lengths are quoted at infinity, and they do shorten as you focus on closer objects. My old manual zoom has a hard stop at infinity.

There’s always been a lot a clatter and drama about “temperature” and the “lens elements getting hot and expanding” therefore “infinity focus changing its position” - I don’t have much faith at all in that explanation. I think we’d need to be inside a blast furnace. .

This is one I’ve heard before and I agree with you, it makes no sense. The linear coefficient of thermal expansion of glass runs in the 3µm/m/K to 9 µm /m/K range. This is well below the manufacturing tolerances of the lens (an in fact getting into the wavelength of light range). The metal used in mounting the optical elements (aluminum and steel) have a considerably higher coefficient of expansion than glass. For aluminum, it’s coefficient of expansion is about three times higher than glass, and if you look at the amount of aluminum in the mechanisms of a lens, you will have a lot larger, yet still insignificant, impact from those components. Manufacturing tolerances, including those related to moving the lens elements around to zoom and focus have a far greater impact than any thermal expansion / contraction impacts.

BUT – on hot days there could be haze on the horizon and that might confuse the AF . . . any AF lens can therefore bounce around attempting to lock onto “infinity focus” . . . hence the explanation about why there is NOT a hard ‘buffer stop’ in AF lenses – and I believe if we dig deep enough into the ‘why’ of Auto Focus Lens Technology, Research and Development, the ‘soft ending at infinity’ explanation is the main reason why (‘modern’ aka ‘Auto Focus’) lenses can go past the infinity marker.

No, going past the lenses infinity setting is going to throw things out of focus. In fact a hard stop would ensure what you suggest would ensure that this could not happen. Instead we have to rely on the camera's electronics to ensure that the camera never attempts to focus past infinity (which would in fact reduce image sharpness).

Again, I believe I am correct that eliminating the hard stop is merely a cost saving measure by the lens manufacturers. If the camera electronics can do it, so why bother with the costly mechanical alignment process on an optical bench for those relatively few people looking for this feature. From a manufacturing process, this is a fairly costly step and the savings will help protect the lenses price point and the manufacturers profit margins.

Only one of my autofocus lenses; the Nikkor AF 50mm f1.8D still has the traditional hard stop at infinity. It is an older screw drive design and relies on the camera's focus motor. I did some testing on it before writing this. Focusing to infinity results in a "soft landing", the drive never does a hard stop on the infinity setting, even though the focus lines up perfectly with the mark on the camera barrel. This is not true for the close up focus as there is a clear "thunk" as the lens hits a hard stop.

[William W]

If you think that setting the lens a bit past the point of the ‘∞’ mark on the lens will make a difference to the final image: then do it and make an A/B comparison: it is an easy enough experiment to do.

If you think that there is NO practical TR & D reason to develop lenses such as to allow them to bounce past ‘∞’ as the AF finds ‘∞’ - then set a lens on a tripod and video the lens turret’s movement as it finds ‘∞’ : you might be surprised how often an AF lens will bounce past and then flick back – every time it does that, it would have hit a BRICK WALL if there was NOT the ability to flick past and come back.

If you think that some zoom lenses do not have marginally different positions where ‘∞’ focus sits dependent upon where the zoom’s focal length is set, then why on some zoom lenses are there more than one Infrared focus re-setting markers and why are they staggered (sometimes substantially) for different zoom lengths?

Sure, some OLDER AF lenses might have an hard stop. I agree. That fact concurs with all that I've written.

And if this functionality is indeed merely a cost saving measure: then I am glad that it has the benefit of allowing all the lenses with improved very fast AF of NOT hitting a big buffer stop at the infinity end of the focus turret.

WW

[Dave Humphries]

Don’t confuse what I initially wrote with what we are now discussing – what I wrote first as advice to focus on infinity was focus the lens to the “∞“ symbol – so if the lens has that symbol AND the lens can focus past it then no worries - just set the focus to the “∞“ mark that will be close enough, because in any case, focusing the lens BEYOND the infinity point will not make the lightning images any worse (or better).

Hi Bill,

I agree with your later posts (e.g. Varifocal zooms, etc.), but on this particular point (my bold above), I'm not so sure.

For AF to work, when it focuses 'past' infinity, or more accurately; when it focuses infinity beyond the sensor, it must surely get softer again, so that the AF can detect this 'wind back a bit' to get an accurate infinity focus. So setting it manually to the end stop is probably going to give a softer image than setting it on the infinity mark.

That said, if you focus just this side of infinity, hyperfocal distance and DoF ought to result in a sharp lightning bolt*, I'm not sure what happens to hyperfocal distance if you have gone past infinity, it might work, it might not, I'd bow to a more learned response than mine (and that might be yours for all I know)

* One thing that kills sharpness photographing white birds is over exposure, so I'd advise keeping iso low and aperture narrow too (I haven't read the entire thread above, so I might be repeating stuff here)

Cheers,

[William W]

Hi Dave – As I’ve mentioned - try it for yourself it’s a reasonably simple test to do.

WW

[Marie Hass]

I am late to this discussion, but for the sake of repeating what others have said, here are my settings:

I have a Canon 7d, I used a 24-105L lens. I used bulb, manual focus, ISO 100, f5.6, WB - auto. To establish "infinity", I did a few preliminary test shots on bulb, exposing long so I could manually establish focus. If I know a storm is coming, I get set up in advance, if I have the chance. I have gotten some fun shots this way.



I have posted some other lightning shots from the other night in album I created in my community albums on CIC, called Nature too. Please tell me what you think.

Marie

[Brownbear]

Thank you.. Beautiful shot, and quite amazing how you captured all of those forks of lightening!

[William W]

Please tell me what you think.

Very nice shot: the trees and the land horizon makes a nice framework.

Also nice to be back on the Original Topic.

WW

[Marie Hass]

Thanks, Bill.

One other thing I forgot to mention, is that I usually do not hold the shutter open any more than 30 seconds. For reasons that the lightning can look over exposed, or that the greenery gets that funky yellow brown green colour. If there was no lightning within that time, I close the shutter and start over. Also, as soon as the lightning bolt finishes, I close the shutter. I have had good success with this technique and the settings described above.

'Rie

[WJT]

Hi Christina, I have jut read this post and see you have had some good advice but I may be able to add some more. The thing to remember is that lightning can jump out of a storm and land 20 mile away so you never know where it will land. This means you have no way of knowing where the next strike will be. This brings me to 3 points:
1.) You cannot know where to focus, so always focus on infinity.
2.) If you use a big aperture setting you will have a shallow depth of field and may also loose a strike that lands right in front of you.
3.) Always use a wide angle lens if the storm is close so that you don't miss the strike. You can always crop it if you get it, but there is nothing worse than missing a close strike (like this one at 100 metres).
1.
Settings for this were 100 ISO, F: 22 and 30 seconds. If I had used a big aperture I would have got the strike on the horizon but missed the big one, If I didn't have a 20 mm lens I would have gotten very little of it, and if I focused on the lightning which I was was seeing in the distance the close strike would have been blurred. hers a few more with the exact same settings. I hope this helps and remember its an addictive hobby but always a great thrill when you get a cracker. Have fun.
2.
3.

[William W]

Not raising the previous discussion about ‘infinity’: but for another reason relevant to the Original Post, I make these comments:

Really - it is actually quite safe and also appropriate good practice to set the focus a little bit in front of infinity considering we would be using apertures of about F/8 to F/16 (or F/22) and likely we will be using a normal to wide angle lens. The large DoF will take care of itself and also, it is not as though the ‘lightning’ will easily appear out of focus in the final image even if it is located near the far point of the DoF limit. . .

Therefore a FOCUS POINT can be chosen to allow an adequately LARGE DoF to render the FOREGROUND in acceptable focus if an in focus foreground will add to the image.

On another point - a serious effort needs to be placed in making the EXPOSURE BALANCED: that is to say we ust choose a shutter speed long enough to trap the lightning strike - but also we must calculate the exposure to best suit the scene - with NO lightning.

***

If I may use IMAGE #3 in the post above as an example to explain these two points:

Assume this scene had NO lightning – then the exposure would be appropriate to make a good night-time landscape shot with well balanced reflections of the pier lights on the water. Also, in this image, even though the Photographer might have focussed at infinity – by using a small aperture of F/22 and a 20mm lens, the DoF is great enough such that the foreground rock formation is nicely in reasonable enough focus to add greatly to the final image as a smooth entry point for the viewer’s eye.

***

Two other comments and again using image #3 as the example:

It is very likely the lens used to make that image was the EF20/2.8, that is a PRIME LENS.
Firstly – a Prime Lens will typically have less Flare and therefore be less prone to Ghost Images and Veiling Flare – two issues which can be a problem when photographing a typical night scene with small areas of very bright illumination.

Secondly that particular lens has FIVE aperture blades: the number of aperture blades is significant when considering Star Flare from point source lights (i.e. the Lights on the Pier).

My taste for any night time scene which contains point source lights is to use only Prime Lenses with FIVE or EIGHT aperture blades (eight being my preferred number).

My reasons are: an ODD number of blades will render a Star Flare with DOUBLE the number of points (five blades will make ten points) and an EVEN number of blades will make a star with THE SAME number of points (eight blades will make eight points).

Eight (or ten) points on a Star Flare makes a very neat and crisp package, IMO, any more points and the Star Flare can become sloppy and poorly defined.

Also, as we stop down the lens, the Star Flare will become more definitive and this is another reason to use smaller apertures for night-scapes, generally.

WW

As an unsolicited comment: Image #3 above, although judging only as it appears in low res: it occurs to be an image of a very high standard - Congratulations.

[WJT]

Hi Bill,

Thanks for the compliment, the lens on image 3 wasn't (unfortunately) the Pro-lens but was the 20/35mm F: 4/5.6, 50mm. But I did learn a lot from your comments, so thank you for that also. The quality of this shot comes from composing an interesting foreground and also from the image sensor on the 5D Mk 11. The F: 22 means that the foreground is sharp, as is the strike which is very important. On this occasion the lightning was striking all around the same distance, however if it had off struck close I would have also got a sharp result. The 30 second shutter speed is used just to allow time to get a strike as I dont have a lightning sensor (yet), but will be sure to have one ny next season which will allow many more possibilities.

[William W]

. . . the 20 – 35 is a very light, samll and very useful lens, I didn’t think of that lens.

It has a short little barrel (by comparative larger W/A zooms).

It would be likely not too prone to Lens Flare, because it is such a very tight little package and very well made – it has 5 blades.

I have looked at buying one on a couple of occassions - though those who own one aren't too eager to sell, usually.

WW

[WJT]

. . . the 20 – 35 is a very light, samll and very useful lens, I didn’t think of that lens.

It has a short little barrel (by comparative larger W/A zooms).

It would be likely not too prone to Lens Flare, because it is such a very tight little package and very well made – it has 5 blades.

I have looked at buying one on a couple of occassions - though those who own one aren't too eager to sell, usually.

WW

Yes I have had a good run with this lens. I wanted the 17-35 F:2.8 but I cant complain about this one.

[Brownbear]

Thank you everyone... Great detailed advice. My next question was going to be, how in the world do you know where to focus for lightening, but not need because I now understand the why's of infinity focus, setting the exposure before hand, and I will also try using a smaller aperture.

And now I just need another storm