# FOURSEVENS (4Sevens) Preon 0 ( P0 ) Review



## subwoofer (Feb 20, 2012)

The FOURSEVENS Preon 0 (P0) is the first FOURSEVENS light I have received with the new logo and branding. FOURSEVENS are in the process of updating the design of their website and product naming/branding which can be seen at the new 'foursevens' website (rather than 4sevens).





The new logo.

The new Preon may be 0 by name, but it is certainly not zero in nature. This is a real little gem.


PART 1 – Initial Impressions:

The first things to strike you about this light are its size, finish and full flood beam.

It is beautifully compact, so much so compared to other AAA lights, you wonder if there will be room for the battery. This is the first AAA light I would personally consider for every-day key-ring carry (new term, EDKRC? maybe not…).

The light is made of stainless steel, and each end is mirror polished with the middle section a plain matt-etched finish. The logo and model are neatly laser etched at the tail end. The lens is slightly domed and instead of a reflector the P0 has a ring of glow in the dark (GITD) material surrounding the XPE emitter which is mounted very close to the lens.

Turn on the P0 and you have a wonderful even full-flood beam. Considering that a light such as this is typically going to be used at short distances, the full flood provides a wide even area of illumination, perfect for general use.



What is in the box:

The P0 is presented in a small box sporting the new FOURSEVENS logo. Unlike other FOURSEVENS lights, the cardboard does not have the velvety feeling finish, instead being a more normal matt black card.






The light is contained in a plastic box, shown here with the lid removed. The light and battery are held in a flock coated foam insert. The instructions are printed on the back of the plastic box.











Looking straight at the lens shows the GITD material surrounding the LED has a green colour. You can’t tell from this image, but the lens is slightly domed and has an o-ring between it and the stainless steel rim of the light’s head.






Those with keen observation, may have noticed a few thin flecks on the lens and light. These are from the flock lining of the box and I hadn’t noticed this before photographing the light. They all came off with a quick wipe of a soft cloth.


Looking inside:

The head has been removed so you can see the positive and negative contacts of the P0. The P0 does not have a normal contact spring, instead having a circular foam pad at the positive terminal which pushes the battery terminal away from the contact as you unscrew the head to turn it off. This method appears to be becoming more common.









Shown here with the head removed and threads visible






The P0 has a magnet on its base allowing it to be attached to any convenient ferrous surface.






Which in this instance was the metal case of the new FOURSEVENS Titanium Pen (brief review coming soon)








Modes and User Interface:

The P0 has two output levels 0.24Lm and 24Lm. Although the specifications don’t mention current control, there is no hint of PMW in either mode.

The light comes on in the low level and if left off for two seconds or longer defaults back to this low level. For the high output, turn off and on again within one second.

This is very simple and intuitive to use.


Batteries and output:

The P0 takes an AAA battery and will work with alkaline and NiMH cells. The P0 is supplied with an alkaline battery, but I have been using NiMH as my preference is for rechargeable batteries.

Note that Li-ion must not be used as the driver is not designed for the higher voltage of li-ion. There is a specific warning from FOURSEVENS to this effect.

The two output levels are well chosen and very useful.



PART 2 – In The Lab

In an attempt to quantify the actual beam profile I developed the following test. There are probably many flaws in my method, but it is simple and easy to carry out and seems to provide a good enough comparison.

The method used was to put the light on the edge of a table 1m from a wall, with a tape measure on the wall. The zero of the scale is placed in the centre of the hotspot and a lux meter is then positioned at points along the scale, with the measurements recorded. Beam shots are often taken with the light shining on a flat white wall, so this method is simply measuring the actual intensity across the beam on a flat surface, not the spherical light emission.

The results are then plotted on a graph.

For the best throw you want to see a sharp peak with less of the distracting spill. For the best flood light the trace should be pretty flat.

The P0’s beam profile shown with the Fenix E01’s beam (which is considered quite floody). An Alkaline battery was used for this test.






At first it may look like the E01 has greater output, but looking at the very flat profile of the P0 you can see it has much more light is output into the wider part of the beam. It has a much more ideal flood beam profile than the E01.


Taking this a little further, I calculated an approximate factor to apply to the lux measurements, as each measurement gets further from the centre of the beam, it corresponds to a larger area onto which the light is falling. It seems to me that this should also be taken into consideration, so I applied these area corrections and came up with this odd looking graph.

The key quantity here is the area under the graph line. This should correspond to the total light output.






This shows the clearly greater total output of the P0 and how much light is spread into the wider spill area, which is as expected for a full flood light.



PART 3 – The beam

The beam is basically the directly emitted light from the LED as there is no reflector to shape the beam.

Light is projected in a cone with approximately 100 degrees opening angle. This is significantly wider than most lights and the entire flood/spill is an even spread of light.








PART 4 – Using the P0

The P0’s size is both a boon and a bane. The downside is that although it can be operated with one hand, because it is so short, it is not that easy. If you have slippery hands there is hardly any grip afforded by the etched finish to help operate it. However, because it is so small, neat and elegant it is simply a pleasure to use, and this positive far outweighs any negatives.

Shown here next to the Fenix E01 and iTP A3, the P0 is dwarfed by these (already compact) popular AAA lights and is not much larger than the battery it houses.






Being a full flood beam, the P0 runs out of steam quickly as the distance increases, but this is not a light designed for throw. Instead you benefit from the wide even spread of light that does not have a hotspot blinding you to the surrounding area, giving a clear view of the entire area you are lighting.

From one side of a room it will light up the entire opposite wall and aimed into a drawer shows you all the contents without having to hunt around with the light.

A curious feature of the flood beam is that as the light is emitted from a very small area, it forms hard-edged shadows (which happen to be very good for shadow puppets).

The low of 0.24lm is great for night time forays and the wide spread of light allowing you to move about easily and stealthily.

The high, with ‘only’ 25lm, still provides good illumination even before your eyes become accustomed to the dark.

Initially I had questioned the practical use of the GITD material around the emitter. It looks good, but does it have any practical value? Well surprisingly yes it does. After using it on high, when you turn it off, there is a soft green glow projected forwards. You could use this for lighting a watch in a theatre/cinema by turning the P0 onto high while keeping the lens pressed against something, just to charge up the GITD, then turn it off and use the soft glow.






Another surprise regarding the GITD material is that eight hours after using the light on high, I awoke with fully dark adapted eyes and was able to see the P0 on my bedside table thanks to the GITD material still glowing faintly. Eight hours later! Ok I needed dark adapted vision to see it and a completely dark room, but this is just the type of situation when you want to be able to find a light easily.

I’ve found the P0 to be an incredibly useful light. Ultra-compact but still using a standard AAA battery instead of button cells. Full-flood beam with two well-chosen light levels, and a magnetic base to let you use it hands-free.


The P0 out and about…






…and in a room with regal connections





Review sample provided by FOURSEVENS.

I’ll update post 2 of this thread once I have some more comments to add....


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## subwoofer (Feb 20, 2012)

Reserved for further comment


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## mrlysle (Feb 20, 2012)

Good review. Looks like we have a least 3 now, all pretty much positive. I still think the driver board is poorly designed, as constant use of Eneloops will definitely cause me problems. I'm sticking with L92's for now, but if they would just have moved the driver components outboard just a smidge, I could be putting my Eneloops to good use. Thanks for your review!


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## Flying Turtle (Feb 20, 2012)

Excellent review, subwoofer. The pics and graphs should be especially useful for those still on the fence about this light. I liked the one with the "Eye" in the background. Maybe we should start submitting shots of the P0, like you said, out and about.

Geoff


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## subwoofer (Feb 20, 2012)

Flying Turtle said:


> Excellent review, subwoofer. The pics and graphs should be especially useful for those still on the fence about this light. I liked the one with the "Eye" in the background. Maybe we should start submitting shots of the P0, like you said, out and about.
> 
> Geoff



Thanks 

Don't tell anyone....  


_but the view of the "Eye" is from the Lord's Terrace which is part of the Palace of Westminster and the 'regal connection' is the 'Robing room' in the same building._


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## DM51 (Feb 22, 2012)

Excellent review! Moving to the Reviews section.

BTW, what were you doing in the Queen's closet??!? :duck:


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## subwoofer (Feb 22, 2012)

DM51 said:


> BTW, what were you doing in the Queen's closet??!? :duck:



DM51, you can't ask me that....a gentleman never tells...


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## tobrien (Feb 22, 2012)

haha nice photos of "The P0 out and about" haha

and I liked that you pointed out the box isn't that velvety feel anymore, I hope 4Sevens isn't making it that way for ALL their boxes, because afaik that's something I've never seen from ANY other manufacturer and it's a REALLY nice touch imo


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## Justintoxicated (Mar 7, 2012)

mrlysle said:


> Good review. Looks like we have a least 3 now, all pretty much positive. I still think the driver board is poorly designed, as constant use of Eneloops will definitely cause me problems. I'm sticking with L92's for now, but if they would just have moved the driver components outboard just a smidge, I could be putting my Eneloops to good use. Thanks for your review!



If your going to leave a comment like that please don't leave me hanging! 
So why can't/shouldn't we use eneloops with this light?


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## yifu (Mar 7, 2012)

Justintoxicated said:


> If your going to leave a comment like that please don't leave me hanging!
> So why can't/shouldn't we use eneloops with this light?


Some people have reported the positive button top not making contact as it is too big for the hole in the foam.


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## shelm (Mar 7, 2012)

yifu said:


> Some people have reported the positive button top not making contact as it is too big for the hole in the foam.


why wasnt this mentioned in the review itself? :shakehead


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## subwoofer (Mar 7, 2012)

shelm said:


> why wasnt this mentioned in the review itself? :shakehead



Hello Mr Shelm, being quite critical of my reviews. Has that become your new hobby?

And the reason is that at the time of testing I had no AAA eneloops available. Does Mr Shelm want to donate a few of every single type of battery available on the market so I can then spend several hours more on each review testing each one for any compatibility issues?

Do you think that the reviewers on CPF are paid to do the reviews? Perhaps if you are so full of criticisms, you should post a few reviews? Eh?


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## shelm (Mar 7, 2012)

okay mr subwoofer, i will stop criticizing your reviews from now on. sorry man, no hard feelings please. ( i'll keep the criticism to my inner self , no prob. )

just try to be more thick-skinned in future. there will always be some minor who gripes about this or that!
now i am thinking that i should have registered with nick _cheekyteen_ instead of _shelm_


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## subwoofer (Mar 8, 2012)

OK cheekyteen.

Just to explain that there are many styles of review, and this is mine. There are specialist in producing beam shot comparisons and highly technical reviews, and it is not my intention to compete with these. Instead I aim to provide more general appeal and real use feedback. I will include what content, tests and photos I can and feel is appropriate to my style of reviewing.


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## Got Lumens? (Apr 17, 2012)

shelm said:


> why wasnt this mentioned in the review itself? :shakehead





subwoofer said:


> OK cheekyteen.
> Just to explain that there are many styles of review, and this is mine. There are specialist in producing beam shot comparisons and highly technical reviews, and it is not my intention to compete with these. Instead I aim to provide more general appeal and real use feedback. I will include what content, tests and photos I can and feel is appropriate to my style of reviewing.


Hello Subwoofer,
Was the review light the first released version?

Shelm was not attacking your review. He was just commenting on facts that have been discovered. I will add that these flaws using Eneloops have been corrected in the updated version. Not all NiMh batteries were an issue, only ones that had a square annode, and not like your tested cells. The Eneloop NiMh battery is recognized, respected, and used worldwide. PM me and I'll send you one for reference :ironic:. The magnet holds the cell firmly in the bottom of the battery tube not the foam washer.

What brand and style of NiMh cells were used in this review?
This information is very valueable for version one owners, and shouldn't effect current shipped lights.

I think this review is very good and informative. I like the style, please take this compliment.
I won't ask about the Queens chambers either. You are privilaged to have such an opportunity to photograph in such a place, and I respect to you being a gentleman .

Do you have any way to label your graphs showing cm's and Lux readings? That will help to read them better. People like myself on the other side of the pond are acustomed to non-metric .

I enjoy your dedication to provide real world photos showing the lights, awsome keep these up they are nice. Your photos show a light as used in the real world environment. :thumbsup:
GL


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## subwoofer (Apr 17, 2012)

Got Lumens? said:


> Hello Subwoofer,
> Was the review light the first released version?
> 
> Shelm was not attacking your review. He was just commenting on facts that have been discovered. I will add that these flaws using Eneloops have been corrected in the updated version. Not all NiMh batteries were an issue, only ones that had a square annode, and not like your tested cells. The Eneloop NiMh battery is recognized, respected, and used worldwide. PM me and I'll send you one for reference :ironic:. The magnet holds the cell firmly in the bottom of the battery tube not the foam washer.
> ...



Hi GL, thanks for your feedback 

The P0 I was testing was the first batch. I measured the space between the two chips on the driver board at 3.3mm. As the standard for the positive contact for an AAA is a maximum of 3.8mm, this would explain the issues found.

Indeed I use Eneloops as my standard Ni-Mh test cell. In this instance, I didn't have any AAA eneloops available (and now unfortunately I need to source some more) so used a mixture of alkaline (duracell) and some LSD AAA ni-mh cells by '7dayshop' which seem to have quite narrow positive terminals. (Thank you for the offer of sending one, but I need to replenish my testing stock, and one is not sufficient - as far as test cells I also prefer to know the history since new and not use any donated cells in case these bias review results).

Thanks for pointing out something I have missed regarding the graphs. The first graph is indeed cms on the horizontal axis and Lux on the vertical - as this is the standard for all my reviews so far, I won't be converting to inches or feet. The second graph is cms on the horizontal axis and a 'quantity' value for which I have not worked out the units, but is derived from like 'lux x area' to give a total quantity of light in that circular zone of the beam.

I enjoy producing the photographic element of my reviews, but this is one of the most time consuming parts, and finding interesting locations can be a challenge. I'll do my best to keep it up.


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## Vernon (Aug 6, 2012)

Thanks for the great review. Just ordered one!


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## skew12 (Aug 22, 2012)

Great review. I'll be grabbing a couple of these soon.


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## AaronG (Oct 7, 2012)

Thanks for the review. I'm very interested in an all flood key chain light. I already have an E05 so I'll have to see how they stack up. I got a couple useful pieces of info here that would warrant being added to the review itself. 

1. The magnet holds the battery in place. I hadn't thought about it but that's genious!
2. The 2nd revision fixes the eneloop problem. I've read that there was a problem but I didn't realise foursevens had done anything about it.

I find it very helpful that you post pics of the light in the tube and head. As well as out and about. These are the types of photos that can't be found on dealer sites. Also your beam profile graph and descriptions are a cool idea.


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