Author Topic: The fallacy of using long lens technique (LLT) at slow shutter speeds  (Read 11038 times)

Bjørn Rørslett

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[ Posted 03 November 2007 - 23:40 Modified and reposted by agreement  ]

What is "long lens technique" ?

It simply is putting one hand on top of the lens, at the tripod collar position and pushing down, whilst you press your face against the finder of the camera, then gently trip the shutter release. Claimed by many people to be the panacea to obtain sharp images with long lenses [some even assert  you can make do with flexing and poorly designed  tripod mounts because of the LLT], but as evidenced here, will actually do the opposite if shutter speeds are slow.

The problem with advocating proper long lens technique (LLT) as the solution to all stability issues with long lenses, is that it ignores the need for shooting at really slow speeds. I don't doubt LLT can secure a sharp image at 1/125 sec, so can any decent tripod collar/tripod combination do equally well. But what happens when you go slower, say approaching 1 sec or even longer? Many times you need to use such speeds for nature photography. I consider 1/15 sec "fast" for long periods of the year and in winter, 1/4 sec to 6 sec are normal.

The following setup was used: a very long and heavy lens with a very sturdy tripod mount  (180-600/8 Nikkor ED, weight 3.2 kg), a very stable tripod (Sachtler ENG 2 CF HD, weight 4 kg), a very stable tripod head (Burzynski), and a very lightweight DSLR (D40). I ran comparisons of a test target of speeds ranging from 1/4 sec to 6 secs, using either proper LLT or no LLT. The camera was on all occasions triggered by a remote control (ML-L3)  to eliminate any influence from manually tripping the shutter release. D40 has no mirror lockup and I did not use a self timer. For a LLT/no LLT comparison, the conditions should be ideal. The lens and tripod are so heavy and stable that you can't see any sign of vibrations when looking through the finder and the lens is tapped. Surely adding more stabilisation by LLT should do nothing to upset this?

I did repeated sequences but all A/B comparisons showed a result similar to the one shown below.

It is readily apparent that even under this set of "optimal" conditions, LLT will deprive the image of detail sharpness. You simply CANNOT touch the lens during a [long] exposure and still have optimal sharpness. This underscores the need for having stable tripod mounts on a long lens. For fast shutter speeds, LLT is OK, but a good tripod mount is better.



So, can a solid support help reduce the vibration caused by the mirror slap between the shutter speeds 1/15 to 1 second without mirror lockup?

Certainly. But even the best support can be inadequate if the tripod mount is poor enough, precisely around say 1/15 sec or so. That is the underlying reason why I complain so much about the long Nikkor mounts. My usage is geared towards slow shutter speeds. I don't do birds in flight or quickly-moving animals. Details and landscapes at dusk or dawn or in the "half-light" period of the year are my speciality.

Of my long lenses, the 200/2 VR is most prone to issues because of its bad tripod collar. It doesn't look that bad but real-life experience shows otherwise. The 300/4.5 ED follows next in terms of poor mount. Usually I can get by in the critical range with MLU with both lenses, though. On the other hand, lenses such as 300/4.5 ED-IF, 300/2.8, 400/3.5, 400/5.6 ED, 500/4, 500/5.6, 500/8, 800/5.6, 800/8, 1000/11, 1200/11, plus the 200-400/4 AIS and 180-600/8 ED all go well even in the critical range, so with any of these, I just shoot away and don't think too much about the actual shutter speed. Thus, I have earlier shown really sharp images taken with the super telephoto 1200/11 at speeds down to around 1/5 sec.

Anthony

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Makes sense to me.  The human body is essentially unstable, so is unlikely to add stability to anything.
Anthony Macaulay

Bjørn Rørslett

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That is an excellent way of stating this obvious yet so frequently overlooked fact, Anthony.

Do have a look at the way birders and wildlife photographers handle their long lenses if the opportunity arises. Most do put their hand on top of the lens.

The_Traveler

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What result would you expect if, instead of your hand, a passive weight were draped over the lens where the hand might be? (like a wide cloth strap with small sandbag at either end.)
 
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Bjørn Rørslett

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You mean, compared to not touching the lens?

With a decent tripod/head, adding weight actually influences the image sharpness much less than one might expect. The important factor is torsional rigidity and coupling between lens and tripod, not weight of the supporting structure as such. You can prove the last point simply by putting camera + lens directly on the ground. The support now is the mass of the entire planet. Yet you can easily get unsharp images.

Frode

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Bjørn, I've got the AFS 200 2.0 VR (first version), do you have a suggestion what to do to improve the tripod collar on this len.

I must say I was thrilled to see this new website. Keep up the good work!

Erik Lund

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The lens collar of the first 200mm AFS is not too bad! A sturdy plate and head/tripod is all that is needed for low light shooting.
Erik Lund

Bjørn Rørslett

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Bjørn, I've got the AFS 200 2.0 VR (first version), do you have a suggestion what to do to improve the tripod collar on this len.

I must say I was thrilled to see this new website. Keep up the good work!

This is my own sample of the AFS 200 mm f/2. The tripod mount has been strengthened by using a thick aluminium piece fastened by long screws going into the original structure. But as the factory design basically is flawed, and replacing the entire rotating collar is out of the question, one cannot really solve the inherent deficiency only alleviate some of the worst drawbacks.



Having a torsionally rigid tripod and a tripod head that couples tightly without adding its own zones of weakness are almost mandatory for long lens usage. A good system should be reliable even at critically slow speeds.

elsa hoffmann

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I never understood how important a tripod collar really is, since I dont shoot long. Much learned here.
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Bjørn Rørslett

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The support issues start appearing with 200 mm class of lenses (FX format) and from there on get progressively worse. Probably by a factor of the (ratio of focal lengths) squared. Thus, a 400 mm lens is at least 4 times more susceptible to support inadequacies as a 200 mm on its own.

Then, of course, you have to add the adverse impact of heat waves and air turbulence that can kill lens sharpness and make even a $10.000 lens deliver soft mush. But these factors aren't really a flaw of the lens, just the photographer not understanding what physical constraints one has to battle with.

Frode

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The support issues start appearing with 200 mm class of lenses (FX format) and from there on get progressively worse. Probably by a factor of the (ratio of focal lengths) squared. Thus, a 400 mm lens is at least 4 times more susceptible to support inadequacies as a 200 mm on its own.

Then, of course, you have to add the adverse impact of heat waves and air turbulence that can kill lens sharpness and make even a $10.000 lens deliver soft mush. But these factors aren't really a flaw of the lens, just the photographer not understanding what physical constraints one has to battle with.

Yes, after I got the D810 I found that my technique using long lenses (200 2.0 / with TC 2X III) had to improve big time in order to get sharp pictures.

As you both suggest, Bjørn and Erik, I think I'll try a more solid tripod/ballhead in order to optimize - suggestions?

Bjørn Rørslett

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What kind of tripod/head are you using now?

Frode

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What kind of tripod/head are you using now?

For my D810, 24, 50, 85 and 200 2.0 VR (sometimes with TC 2X III) I use:

Berlebach Report 3002
Feisol Classic (3 legs).
Redged RNB3 ballhead

I know, "can only get better" :-).

Bjørn Rørslett

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Yes, this can be bettered. Is your Berlebach one of those classic wooden tripods made in ash?

I only use Sachtler, Erik swears by the bigger Gitzo tripods. There are arguments for and against both brands and only your usage can decide which is the better suited for you. They are top-of-the-line products in different areas of photography. Torsional rigidity of the tripod is important; weight, not so much.

A beefier tripod head is highly important as well. I keep to the Burzynski as they have served me well for two decades, but there is a huge variety of good ball heads out there. Do ensure it is as compact as possible and that the linkage from the mounting platform (which should be Arca-Swiss type) to the ball itself is robust and short. For long lenses I much prefer using fluid heads, but then the weight, size, and pricing, all increase to another level.  The best fluid heads might cost 5x that of their "legs".

Using mirror lock-up and a cable release sometimes help you overcome  an otherwise impossible situation.

Switching off VR when the lens is tripod-mounted usually helps as well.

Frode

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Yes, this can be bettered. Is your Berlebach one of those classic wooden tripods made in ash?

I only use Sachtler, Erik swears by the bigger Gitzo tripods. There are arguments for and against both brands and only your usage can decide which is the better suited for you. They are top-of-the-line products in different areas of photography. Torsional rigidity of the tripod is important; weight, not so much.

A beefier tripod head is highly important as well. I keep to the Burzynski as they have served me well for two decades, but there is a huge variety of good ball heads out there. Do ensure it is as compact as possible and that the linkage from the mounting platform (which should be Arca-Swiss type) to the ball itself is robust and short. For long lenses I much prefer using fluid heads, but then the weight, size, and pricing, all increase to another level.  The best fluid heads might cost 5x that of their "legs".

Using mirror lock-up and a cable release sometimes help you overcome  an otherwise impossible situation.

Switching off VR when the lens is tripod-mounted usually helps as well.

Yes, the Berlebach is made of wood, Bjørn.

Both Sachtler and Gitzo are interesting, but what model?

Burzynski would have been great, but as far as I understand it's very difficult to get our hands on those... RRS BH55 might do?

Latent I'v been using MUP and Cable release with good results.

Yes, VR is set to off when used on tripod.