DIY incident light meter lens cap

Weston invercone modified

I always wanted one of those nice lens caps that allegedly let you take incident exposure readings with your camera, without having to lug around an actual external light meter.

If you carry something with you, after all, better be useful in more than one way, right? This is basic backpacking philosophy.

What thrown me back was the fact that these things – basically a filter mount with a piece of white plastic on top – can cost up to 60 euro…somehow it didn’t seem right.

And no, I’m pretty sure that a white ping pong ball will not give you the same results. If you go all the trouble to take an incident reading you do it because what you want is precision, not to screw up your exposure cheaping out on a vital piece of equipment. By the way, this is the same motive I don’t trust the 1$ chinese knock-offs.

Moreover, all those cheap alternatives are sold mostly as a mean to set the white balance – I shoot in raw, so I tend to correct it in post, so I don’t care. What I wanted, I repeat, was the possibility to use the camera like an incident meter, without having to carry one.

Fast forward till this month: in addition to a Rolleicord I bought last year from eBay – a camera claimed to be in “superb state” that required some serious full disassebly and CLA job to became operational… – I received a Weston Invercone.

If you are asking yourself “what the **** he’s blabbing about?” check the following link:

From what I gather it was an accessory for the Master line of Weston exposure meters that gave the possibility to take incident readings, so the plastic is of the right kind and shape for the job.

Actually, according to the aforementioned website, “this little chunk of white plastic […] is in fact an extraordinary piece of design which has made the Weston the most accurate incident light meter in the world”.

The Weston meters are, I think, most if not all selenium based ones, meaning that even if you can find one operational it will probably be out of calibration or about to die.

But the Invercone happens to sit pretty nicely inside the 49mm ring of a beaten up old filter! You will just have to:

– cut or file a bit of the corners at the flat base on the back of the Invercone, tearing away the little metal strip at the same time

– glue together the two halves of the Invercone – front and back – that will almost certainly come apart once you tore away the metal strip; just a dot or two will do the trick

– unscrew or pop out – depending on the brand – the glass from its filter metal ring

– glue the Invercone inside the filter ring (cyanoacrylate works like a charm), shielding the slight gap that will remain at the base with a piece of something neutrally colored. I used a piece of camera insulation self-adhesive foam, but you can use also, for example, the foam that comes inside pen and flashlight boxes or whatever you have at your disposal, as long it is gray or, better still, black.

Weston invercone inside part

Congratulations, now you have a fully functional, professionally looking, incident meter lens cap! Just point it towards the direction from which the light is coming – not towards the subject! – and take a reading for the exposure. All set.

Obviously you can use a different filter diameter, as long as it fits the Invercone. For example I’m quite sure that with a 52mm filter you could even avoid filing down the corners. I used a 49mm filter just because I had it, and as it happens is the same diameter of some of my most used lenses.

Now for the prices: my Invercone came with other stuff, like I said, but I see them on eBay all the time going for like 8 bucks top – only the cone, without a meter.

If you have to spring cash because you don’t have an old filter in the correct size buy a step up ring and not a filter, so you will not have to unscrew the glass; even simpler. This will set you back another 1 or 2 euro.

Does it pay in the end going all this trouble and taking incident readings? Well, it depends.

The differences between my readings – (spot, interpreted by my own brain, not by a camera chip) – and the ones taken with the help of the Invercone are usually within 1-2 third of a stop. However I grow up spending my weekly allowance on professional slide film I almost cannot afford at the time, so I had to learn pretty quickly to expose correctly. As they say: your mileage may vary!


If you shoot jpeg

Yes it is worth the trouble, because, given your files have less latitude in post to recover from mistakes, whatever you can use to nail the exposure is more than welcome. And as a bonus you will be able to nail the white balance as well.

If you shoot raw

It might be useful, especially in reportage situations when you can not miss the picture (obviously taking a reading of the scene, and then sticking with it).

In more relaxed settings – say landscape – I don’t think so. The problem is that with raw the smart thing to do, if one has time, is to expose to maximize the amount of light information collected – so not to expose for the correct visual rendering of the scene; it will be in post, comfortably sitting in front of a big calibrated display, that you will choose the right look for each image.

Happy pictures!


DIY Hasselblad flash shoe adapter

Hasselblad diy flash shoe adapter

An Hasselblad is a terrific camera for portraits – well, for almost everything really.

But if you want to shoot with a flash, connecting the syncro cable to the lens, you will be left with no place to put the wireless remote trigger body – because you are using the flash off-camera, right? (If not: come on, you’re using an Hasselblad, don’t light your pictures like you’re using a point and shot…)

To be able to attach the remote trigger or a flash to the camera you’d need the Hasselblad flash hot shoe adapter, that I’ve seen going anywhere from 30 (rarely) to 60 or more euro.

Now yes, I’m sure it is well crafted and ingegnerized, but for crying out loud: 60 bucks for an hot shoe adapter??? No way!

Luckily you can make your own version pretty easily, in just a couple of minutes work.

You will need:

– ideally a piece of rail of the same size of the Hasselblad accessory shoe mount (8mm wide x 35mm long)

– if, like is most likely, you don’t have one of those handy you can just make your own with a piece of aluminum sheet

– a flash shoe. I found one in my junk bin, but you can buy those for 1 euro top

– cyanoacrylate glue / superglue / liquid metal glue (whichever you put your hands on first)


Hasselblad accessory shoe

Hasselblad accessory shoe with flash shoe adapter in place


All that you have to do is:

1a) if you have the rail of the correct measure: just cut it to the right length and bend slightly one of the ends, so it will not slide out of its socket

1b) if you have to make do with the aluminum sheet: bend it in a “letter C” shape – check the picture under the post title -, then bend slightly one of the ends like in 1a

2) glue the flash shoe on the rail. Let it rest a few minutes to give the glue enough time to properly set


Now go spend on film what you just saved, or put it in the saving jar for a digital back 🙂


Hasselblad lenses 5c DIY unjamming tool

Hasselblad DIY unjamming tool
I don’t know if I have to explain this…the picture pretty much speaks by itself.


1) pick a 5 euro cents coin

2) using a stepped bit – easier – or a normal bit drill a hole in the center

3) pass a piece of cord trough the hole and make a node creating a loop – I used a bit of paracord (parachute cord) I had laying around that it is worth more than the coin 🙂

4) attach it anywhere you want: your keys, the Hasselblad strap, your backpack.


The important thing is that you will have this object with you if (when) a jamming should happen.

Hell, this thing is so cheap and easy to do that you can also make tens of them, and spread them everywhere!


Review: Velbon Ultra Rexi L tripod and a quick and dirty mod

Travel Tripod Velbon Ultra Rexi L

I was shopping for a hiking tripod, i.e. one light enough to not break my back like the 8Kg / 17,6 Lbs monster I usually carry around, but stable enough to let me take un-blurred pictures even with medium / large format equipment. Oh, and it should haven’t costed an arm and a leg…so one of the Gitzo Mountaineer series was a no-start.

After checking the reviews on the internet I narrowed my choice to the Benro Travel Flat A2190T vs. the Velbon Ultra Rexi L.

They are both pretty light, in the order of 1,5 Kg / 3.3 Lbs. The attractive of the Benro was, well, that it folds perfectly flat. This would came pretty handy when you strap it against a backpack – or if you have to stuff it in a suitcase. What made me chose the Velbon Ultra Rexi L over it was that the Benro, because of its design constraints, cannot spread the legs to to be lowered enough; the fact that I read in more than a user review that it is flimsy did’t help its cause.


The review

The Velbon Ultra Rexi L proved to be pretty much almost perfect for my needs. My only concerns are:

1) the system to open the legs is pretty handy, but sometimes the legs seem locked when they are not. I ascribe this as just a matter of habitude, and not a design fault. Now I’ve taken the habit of just pushing on the tripod head to check for some unlocked section before putting the camera on*

2) reliability of the system used to lock the legs. It looks pretty strong, but only time will tell if dirt and debris will have the best of it**

3) the tripod has the unusual, for a tripod, 1/4″ screw – the same you find on the bottom of every camera. Given that almost any serious tripod head comes with a classic 3/8″ hole – and that anyway Velbon gives you along with the tripod a nice tool kit – why on Earth not include a small ultra-cheap adapter screw? I had one laying around, but still…


Last – and this is what this post is really about, so drum roll please:

4) the tripod does not have a hook under the center column to hang a bag if the weather is windy, to add stability


Given that:

1) is pretty much my fault, after a life spent using other kinds of locking systems. Besides, this system is MUCH faster to open / close than the traditional ones*

2) is more a concern for a technology I never used before than a fault**

3) is irritating and a lack of forward thinking of the marketing department, but hardly a defect


the only real issue impacting usability is 4), but that is easily fixed.


The quick and dirty modification

The tools

You will need:

– a drill, but in a pinch you can also operate the drill bit by hand

– a drill bit suited for plastic or, way better, a stepped bit like the one on the right

– an eye screw and a plug / conical anchor or, better still if you can find one: an eye bolt, a suitable nut and a washer


I used an eye screw, with a closed circular hook, because on pretty much all of my photographic gear I have carabiners. If you don’t use them you probably will better be using an open hook, to hang on it the shoulder strap of your bag.


– unscrew the plastic cap from the bottom of the center column

– drill a 6mm hole straight in its center – in the picture above the anchor is already half inserted in the hole

– pass the bolt through and lock it from the inside of the cap with the washer and than the nut – or in my case with the anchor


By the way, if you want to save further on the tripod weight you can unscrew the bottom part of the center column but still screw the cap on the remaining bit. I did this, because I never use the center column if I can help it; doing so is like using a monopod with three legs, not a tripod, and greatly decreases stability.


* Yes, it was definitively a matter of habitude. Now that I’ve grown accustomed to this system I’m feeling extremely uncomfortable when I use my others tripods with their more traditional leg locks!

** For now I’ve dragged it in mud, water, grass and lugged it around quite a few woods and mountaintops, but it is still going strong


Winter is coming! A DIY tripod substitute for walks in the snow

Tripod stickWhen you walk in the woods in winter, with your trusted pair of snowshoes, you usually try to travel light. It has been proved that walking with the snowshoes, while it’s a lot of fun, makes you spend 30% more energy; so we tend to travel as light as possible. And giving that we cannot avoid to carry lenses & cameras & safety stuff we have to skim down somewhere else.

More, we all tend to buy the smallest snowshoes possible, i.e. the ones that barely support our own weight + a normal backpack, because a pair of oversized snowshoes are cumbersome when you have to take them out and have them hanging & banging on the backpack. But add to the equation the weight of an hefty tripod and we literally start to sink in fresh snow…

Last, but not least, we normally are pretty busy messing with gloves and walking sticks, so often we do not have enough hands. But here come the solution!

Snow stick top

It’s pretty simple: just unscrew the bit that keeps the laces tightened to the stick, insert in the slot, under the laces, a piece of wood or plastic (to give the screw something solid on which to hold) and put (using a longer screw, not the one that comes with your sticks) a tripod head with a fast release plate on top on one of the sticks. Done!

Sure, it is not a support as solid as a tripod, and you can forget to use it for long exposures (even though if you sink it into the snow deep enough…). But, especially if you use a mirrorless or a light compact camera (say a Leica…) you’re set. To add stability you may also pull toward youself the lace of the stick while pushing the stick itself away.

Total cost ranges from 0 (if you have an old tripod head like I did, just laying around) to 20-25 € for a good quality, Arca compatible plate.

Total weigh is negligible, a few grams on top of an object that you will carry anyway.

And, by the way, the same thing (although this one involves drilling an hole into the metal head) can be done on a ax pick to use when there is no snow. But in this case, quite frankly, I prefer to carry my 9Kg tripod!