# NEW FF Body that is able to take EF-S Lens



## knocker (Jun 19, 2012)

Hi all
OK I might be missing the point here but is it not possible to invent/build from scratch a "FULL FRAME" body that can use both EF-S and EF lenses? I understand about the mirror clearance and all that, but is it just not possible or is it a marketing issue?

Your thoughts please


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## maxxevv (Jun 19, 2012)

Its gonna be a lot of compromises if you want it that way. 

Firstly, to clear the mirror/prism, your viewfinder would be something in the range of 60-70% view. 

Secondly, to clear the mirror/prism, your AF array would have to be as small as an APS-C one. Meaning it covers barely 1/3 or even 1/4 of the sensor area. 

Thirdly, its probably more sensible to engineer an APS-H sensor camera that can take EF-S lenses instead. Since its just a minor tweak as someone has experimented on the 1DmkIII some years back. (Think it was the EF-S 10-22 lens ?? ) And probably make it at a more attractive price point for EF-S/ APS-C upgraders.


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## VirtualRain (Jun 19, 2012)

It's silly if you think about it... The image circle of an EF-S lens is not large enough to fill a FF sensor. Even if you could make it work mechanically it will look like you have massive black vignetting on all your images, forcing you to crop the image to what a crop sensor would produce.


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## SpareImp (Jun 19, 2012)

I thought they made the EF-S lenses so that they could make them more compact than those who work on FF. Wouldn't it be kind of backwards to make a FF-camera that's compatible?


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## wickidwombat (Jun 20, 2012)

VirtualRain said:


> It's silly if you think about it... The image circle of an EF-S lens is not large enough to fill a FF sensor. Even if you could make it work mechanically it will look like you have massive black vignetting on all your images, forcing you to crop the image to what a crop sensor would produce.



kind of like using a tamron lens....


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## TTMartin (Jun 20, 2012)

I most certainly can be done with a mirrorless full frame camera.
As for if it makes any sense, Nikon does it, so I guess that answers the question.
Depending on your views of Nikon that could mean it is the worlds best idea, or it makes no sense at all.


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## paul13walnut5 (Jun 20, 2012)

> As for if it makes any sense, Nikon does it, so I guess that answers the question.



Nikon does it, but the camera crops when it detects DX lenses, so really you are worse off as you are back to square 1 with the field of view, but your cameras resolution has dropped by 60%.

Kind of having a D800 and turning it into a D7000.

Nothing wrong with the D7000 of course, but if you have a D700 then it becomes more like a D70...

The canon system is not ideal, I don't quite understand why Sigma and Tamron can make UWA lenses for APS-C cameras that retain the AF mount and don't break FF cameras.

In fact, thats your answer, buy off-brand DC Di lenses etc, mount them on your full frame and crop...

Makes perfect sense, unlike say just using the very good APS-C cameras the EF-s lenses are designed for.


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## Hillsilly (Jun 20, 2012)

I'm sure its possible. As mentioned, Nikon cameras can do it and I'm sure Canon engineers are just as capable. With Nikon, If you mount a DX lens (similar to EF-S) the camera camera recognises this and works in "crop" mode. Its not ideal as you potentially lose a lot of megapixels. But otherwise, everything works fine.

If Canon, can't get things to work properly, due to mirror sizes, lens element to sensor distances etc then there's an easy solution. The camera just works in mirror-up mode with EF-S lenses. Rather than using the viewfinder, you can autofocus and frame via liveview. Its really not that hard. In fact, this would work really well with the new touch screens. While there are some historical reasons why they weren't compatible, I suspect that some of the innovations seen in the 650D will be seen in the next FF and this will give the camera the data processing capabilty to mount EF-S lenses. If Canon doesn't do this, the decision will be purely sales driven. It forces people to but new lenses if they move from APS-C to FF.


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## preppyak (Jun 20, 2012)

Hillsilly said:


> If Canon doesn't do this, the decision will be purely sales driven. It forces people to but new lenses if they move from APS-C to FF.


Or it will be driven by Canon not wanting users confused about why their lenses cause a huge black circle around their image on their $2000+ camera. Gonna be a lot of pissed off users when they find out "using" an EF-S lens means this







Besides, if you're putting $2k+ into your camera body...what EF-S lens would you even want to mount on it? I guess I could see someone wanting to use the 10-22 or 17-55...but, Canon make full-frame versions at the same price points basically (17-40 and 24-70)


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## unfocused (Jun 20, 2012)

I kind of hesitate to bring this up as I am bored with the whole APS-H thing, but I am curious. Has anyone mounted the Tokina 11-16 on a 1D? Does it vignette at the wide end?


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## edawg (Jun 20, 2012)

Putting an EF-S 10-20mm lens on a full frame would give one heck of a field of view. Definitely would be cool, but not possible optically.


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## wickidwombat (Jun 20, 2012)

unfocused said:


> I kind of hesitate to bring this up as I am bored with the whole APS-H thing, but I am curious. Has anyone mounted the Tokina 11-16 on a 1D? Does it vignette at the wide end?



http://photography-on-the.net/forum/showthread.php?t=997698

this thread indicates vignetting shows up at about 12mm


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## briansquibb (Jun 20, 2012)

The 8-15 vignettes at 8mm : : :


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## wickidwombat (Jun 20, 2012)

briansquibb said:


> The 8-15 vignettes at 8mm : : :



LOL

is it a progressive change from rectangle at 15mm to circle at 8mm?


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## briansquibb (Jun 20, 2012)

wickidwombat said:


> briansquibb said:
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> > The 8-15 vignettes at 8mm : : :
> ...



Yes  It is the inbetweens that give the best artistic effects.

Makes me laugh when the APS-C talk about their ultra wide angle lens - this is lens is 8mm whereas the APS-C is the equivalent of 16. OK it is a fisheye - but there is the 14mm .....

This was taken with the [email protected]


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## hyles (Jun 20, 2012)

EF-S lenses where created with the back lens element projecting more inside mirror box. This allows light to reach the sensor more vertically, But it needed on aps-c camera a smaller mirror. Even if electronically an ef-s lens is able to work with a FF body, it is impossible to mount it because the plastic ring on the back of the lens that would hit the mirror. Someone has removed this plastic on some ef-s lens to mount and use them on FF, but you would end up with loosing a lot of megapixel cropping images. 
I think that if you want to use ef-s lens you better have a crop sensor camera. Even if nikon allows compatibility of their FX camera with aps-c lenses, i think it is quite a useless option.
Diego


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## wickidwombat (Jun 20, 2012)

hyles said:


> i think it is quite a useless option.



it's not entirely useless
if the reduced file size of the images can give a faster FPS burst and deeper sustained buffer 
ie the camera detects the lens and only processes an APS-C sized image from the sensor resulting in smaller data for each image but can still use the full processing power this sort of function would be pretty handy for action shooters I would think


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## hyles (Jun 20, 2012)

wickidwombat said:


> hyles said:
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> > i think it is quite a useless option.
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Off course you will have a faster camera then the FF, but i can't see the point buying 3300 euros, 22mp camera to use it as a 12mp aps-c camera, when you can save money with a 18mp very fast 7D. Thinking of nikon, if i wanted to use my aps-c lenses i would rather buy d7000/d300s than any FF used in crop mode.
Diego


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## Neeneko (Jun 20, 2012)

Hillsilly said:


> I'm sure its possible. As mentioned, Nikon cameras can do it and I'm sure Canon engineers are just as capable. With Nikon, If you mount a DX lens (similar to EF-S) the camera camera recognises this and works in "crop" mode. Its not ideal as you potentially lose a lot of megapixels. But otherwise, everything works fine.



*nods* at which point, you might as well just take regular FF pictures and crop them in post. I always thought the Nikon thing was a bit of a dirty trick, kinda like how Canon quietly changes settings at low f stops to make the user think they are getting extra light... it is giving the user what they visually expect, sorta, but only because you are not giving them what they mechanically expect.


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## briansquibb (Jun 20, 2012)

hyles said:


> wickidwombat said:
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That is what the D800 does


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## wickidwombat (Jun 20, 2012)

hyles said:


> wickidwombat said:
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Nikon cant use EF-S lenses  sorry just teasing I know you meant the Nikkor DX lenses


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## briansquibb (Jun 20, 2012)

Neeneko said:


> Hillsilly said:
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> 
> > a bit of a dirty trick, kinda like how Canon quietly changes settings at low f stops to make the user think they are getting extra light... it is giving the user what they visually expect, sorta, but only because you are not giving them what they mechanically expect.
> ...


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## Radiating (Jun 20, 2012)

When I switched to full frame I ran the calculations and found that for EVERY SINGLE EF-S lens from focal lengths 10mm to 250mm (16mm-400mm equivalent) it's full frame equivalent lens would be always substantially much *better*, almost always *cheaper*, could acheive better subject isolation with *shallower DOF* and be much much *sharper*. In fact full frame lenses typically have twice the resolution of their crop counterparts. 

Example:

10-22mm vs 17-40mm = lens is cheaper, has 202% the resolution, has 1-2 stops shallower DOF and has a longer reach on the long end, and is weather sealed.

17-55mm IS vs 24-105mm IS = lens is cheaper, has 205% the resolution, has 0.5 stops shallower DOF, and is both longer and wider, and is weather sealed.

55-250mm IS vs 70-300mm IS = lens is only $150 more, has 186% the resolution, has 1-1.5 stops shallower DOF, is wider, but also only has 300mm vs 400mm of reach, HOWEVER it is so much sharper that cropping it actually results in a 6% sharper image which has shallower DOF. 

18-200mm IS vs Tamron 28-300mm XR (full frame superzoom) = lens is $100 less, has virtually identical resolution, has a 1 stops shallower DOF, is slightly wider but is slightly shorter (29 vs 28mm 320 vs 300mm).

Remember crop lenses need to have their focal length multiplied by 1.6 and 1.5 stops subtracted from their aperture to compare them to full frame lenses. So a 17-55mm f/2.8 lens is the equivalent of a full frame 28-90mm f/4.5.

The point is that there is zero image quality benefit and it would cost more to use EF-S lenses on full frame than their EF counterparts. It's pointless and engineering a body with this function would also be pointless.

Nikon's dogma as a company is compatabilty that's why you can use 50 year old lenses on their bodies which still work. Even if that compatability is pointless. 

Keep in mind my argument is before you consider that you'd be working with very few megapixels if you were to make EF-S lenses compatible with full frame bodies. That really sinks the whole idea. 

The only major argument for being able to use EF-S lenses on full frame is lens sharing. However if you actually study the possibility of lens sharing it's much better to share EF lenses between a crop and full frame than EF-S lenses between a crop and full frame. 

EF lenses on crop tend to be about 10% worse in resolution than their EF-S counterparts. 

So if you were to share EF-S lenses you'd lose 50% of your resolution just at the lens nevermind the megapixels on one body. If you share EF lenses you only lose 10%. I'm pretty sure most people would much rather have 10% less resolution than 50% so it's much much much better to only have EF lenses and share those with your crop than to have EF-S lenses and share those with your full frame instead of getting the EF counterparts. Enabling people to share EF-S lenses between their full frame and crop cameras would be pointless, as it's just giving them the option to have much worse and more expensive gear.

Hope that clears things up. If anything making EF-S lenses incompatible with full frame motivates people to not use EF-S lenses on full frame which is better and cheaper for them in every way.

Hope that helps.


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## Neeneko (Jun 20, 2012)

briansquibb said:


> Neeneko said:
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> > a bit of a dirty trick, kinda like how Canon quietly changes settings at low f stops to make the user think they are getting extra light... it is giving the user what they visually expect, sorta, but only because you are not giving them what they mechanically expect.
> ...



I don't have the link handy, but it was discovered a while back that digital sensors, because of their geometry, do not get the full benefits of low fstops. A much narrower family of angles actually register, so a good chunk of the extra light a really fast lens lets in does not actually register with the sensor. Canon quietly increases the ISO when it detects low apertures to give the appearance the extra light is doing more then it is. If you use manual aperture lenses (with no reporting) the behavior does not trigger and you can see the effect in play.


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## Bruce Photography (Jun 20, 2012)

wickidwombat said:


> hyles said:
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Actually I really love the format changes the D800 does so effortlessly. It isn't that I want to ever buy DX lenes (I don't except to try the 18-300), but when using the 2x extender on the 70-200 at 200 I get 400mm. But instead of cropping in post, I can switch to DX format and I'm now using a crop window in the view finder for DX as if I was using a 600mm lens. Now for Canon you are right. As long as 22MP is full frame you can't afford to crop anything. But with 36MP you can choose to crop now or crop later and save all card/disk real estate. When I'm doing birding, this is really quite nice because 15MP is ok if I can use all of it. Actually they have quite a few format crops that I can choose at the touch of a button. Perhaps this will turn out to be the true utility of a large MP sensor in addition to full MP landscapes full of detail for my large prints.


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## briansquibb (Jun 20, 2012)

Neeneko said:


> briansquibb said:
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So this only applies to the very fast lens? Why doesn't the change in ISO register?

I wonder where this starts happening? f/2, f/4?


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## noisejammer (Jun 20, 2012)

briansquibb said:


> So this only applies to the very fast lens? Why doesn't the change in ISO register?
> 
> I wonder where this starts happening? f/2, f/4?


 It depends on the camera. The 7D is worst but it affects all digital cameras (not just Canon.)
For the 5D2, the effect starts at about f/2.4. It's significant at f/1.4 and between f/1.2 and f/1.4 you get almost no benefit from the extra light. I posted my results on POTN a couple of weeks back. Here's a link http://photography-on-the.net/forum/showthread.php?t=1165164&page=3 and a second plot of my results... http://photography-on-the.net/forum/showthread.php?t=1165164&page=5. A few others also verified the effect with experiments.

The result of the post was that owners of the 50L and 85L started making really unpleasant comments. This was regretable but the fact is that Canon (and Nikon, Pentax, Sony) all increase the ISO to make it look like your fast glass is actually doing something for you.


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## briansquibb (Jun 20, 2012)

noisejammer said:


> briansquibb said:
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> > So this only applies to the very fast lens? Why doesn't the change in ISO register?
> ...



Many thanks - very useful info knowing that v fast lens buys shallow DOF and (perhaps) better bg blur and bokeh


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## wickidwombat (Jun 20, 2012)

so are you saying that say you are shooting a concert in very low light with a 50 f1.4
@ f1.4 3200 iso
you would be better off shooting at say f2.2 @iso 8000
or f2.8 @iso 12800

because from an iso noise POV this is what is happening anyway?


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## noisejammer (Jun 20, 2012)

briansquibb said:


> Many thanks - very useful info knowing that v fast lens buys shallow DOF and (perhaps) better bg blur and bokeh


Actually no - the point is that light from the perifery of the lens does not make it to the active part of the sensor and so it cannot contribute to the image or shallow DoF. Mounted on a 5D2, a 50L can barely perform like a 50/1.6 (albeit a very good one.)


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## noisejammer (Jun 20, 2012)

wickidwombat said:


> so are you saying that say you are shooting a concert in very low light with a 50 f1.4
> @ f1.4 3200 iso
> you would be better off shooting at say f2.2 @iso 8000
> or f2.8 @iso 12800
> ...


Not quite - but let's assume the f/1.4 lens collects light like a f/1.7 lens, then you would get the same effect using a f/1.7 lens and boosting the ISO by 1/3 EV. Of course, since a stopped down fast lens almost always outperforms a wide open slow one, you would probably sacrifice vignetting and perhaps image quality. 

As I commented earlier, it is strongly dependent on the camera and I invite you to read the DxO Labs article that my POTN post links to.


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## briansquibb (Jun 20, 2012)

noisejammer said:


> briansquibb said:
> 
> 
> > Many thanks - very useful info knowing that v fast lens buys shallow DOF and (perhaps) better bg blur and bokeh
> ...



Surely the DOF is related to the aperture of the lens not the amount of light reaching the sensor? Likewise the bg blur and bokeh

ie a 50L @ 1.2 with still have the dof of a 1.2 even though the light is only that of a 1.6??


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## traveller (Jun 20, 2012)

The reduced light transmission effect that is being referred to with large aperture lenses, is applicable to some extent to all lenses. It exists because the lens f-stop is only a theoretical measure of how much light a lens transmits to the film/sensor. In practice, glass absorbs some of the light and reflects another proportion (hence the importance of good lens coatings - see http://www.canonrumors.com/tech-articles/all-about-lens-coatings/). The effect of this is that less light reaches the film/sensor than the aperture of the lens would theoretically allow in a perfect lens; the measure of actual transmission of light through a lens is known as the t-stop (note that this is very important to cinema camera lenses -hence why they are often specified in t-stops: see the new Canon cinema-EOS lenses). 

None of the above is unique to digital it is a fundamental part of lens physics. Thus lenses with a higher number of elements will (all else being equal) have a lower t-stop for an equivalent f-stop than lenses with fewer elements. This has negative t-stop implications for fast zoom lenses and lens based image stabilisation systems. There is another aspect to this, the structure of silicon sensors require light to hit at an angle that is closer to 90 degrees to their plane than was the case with film. This was ostensibly what required many lenses to be redesigned 'for digital' several years ago (believe that if you will). Wider apertures transmit light travelling at more oblique angles than smaller apertures, which is the factor that may reduce transmission of fast lenses more when used with digital sensors vis-a-vis film. 

Some might argue that t-stop doesn't really matter for large aperture primes; with the superb high-ISO performance of today's CMOS sensors, it is shallow depth of field that is their primary usage, rather than for increasing shutter speed. This may not hold true because of the loss of detection of the oblique angle rays; to quote The Luminous Landscape: 

"The DxO measurements to date prove that the marginal light rays just don’t hit the sensor. The point regarding depth of field is that these rays are also responsible for a larger blur spot when out of focus. If they are lost, they not only don’t contribute to the light intensity at the sensor, but they also don’t blur the out of focus planes as much as you would expect at wide apertures." [http://www.luminous-landscape.com/essays/an_open_letter_to_the_major_camera_manufacturers.shtml] 

So far, I haven't seen anyone empirically test a large aperture prime on digital versus film to determine how much of a problem this is in the real world... any takers?


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## BjornO (Jun 21, 2012)

May be a TC can solve the problem. I know someone have used a Kenko 1.4 TC on Sigma UWA's with success (more or less).

http://photography-on-the.net/forum/showthread.php?t=909337

I dont know if there are any TC on the market which accepts EF-S lenses, but perhaps...

From the samples I have seen, the quality is on the same level as with a crop body.


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## LetTheRightLensIn (Jun 21, 2012)

maxxevv said:


> Its gonna be a lot of compromises if you want it that way.
> 
> Firstly, to clear the mirror/prism, your viewfinder would be something in the range of 60-70% view.



yeah you'd have a horrible little VF with impossibly small to use coverage.



> Secondly, to clear the mirror/prism, your AF array would have to be as small as an APS-C one. Meaning it covers barely 1/3 or even 1/4 of the sensor area.



No the AF arrays have been pretty much the same size in all DSLR frame sizes APS-C,APS_H or FF. Using a full APS-C VF-szied secondary mirror for AF would even fit the 5D3 AF into APS-C.


Anyway you'd get a lot of vignetting and even hard-vignetting so I don't see how it is worth the bother even if it didn't make the VF useless.


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## knocker (Jun 21, 2012)

Wow!

When I posted the question I got 1 reply and thought oh well it must be a bone question never mind. Then I have another look and now I have this lot must be from over the pond me thinks 

All of you thank you for the fantastic response I now understand it all a lot better.

The reason for the question was I have 400d, 40d, and the 7d along with

Canon FD 50mm F1.8+FD to ES conv = 1.4
Sigma 10-20mm f/4-5.6 EX DC HSM
Canon EF-S15-85mm f/3.5-5.6 IS USM
Sigma 17-70mm F2.8-4.5 DC Macro
Sigma 18-200mm F3.5-6.3 DC OS
Canon EF-S 18-55mm f/3.5-5.6
Canon EF 28-135mm f/3.5-5.6 IS USM
Sigma 30mm f/1.4 EX DC HSM
Canon EF 50mm f/1.8 II
Canon EF-S 60mm f/2.8 Macro USM
Canon EF 70-300mm f/4-5.6 IS USM
Canon EF 70-200mm f4 L IS II USM
Sigma 150-500mm f5.0-6.3 DG OS HSM
2x EX DG Tele Converter on 70-200 Canon
2x EX DG Tele Converter on 150-500 Sigma

And was wondering if I should get rid of the EF-S and the 3 body's if the new 7D was full frame or do I keep them in case something was invented that could use both but now I understand that the most economical way forward would be to get rid of them

Thanks again for all the VERY informative reply's

I have been on a lot of forums and there is not one bad post in this lot normally on a forum you get at least one dick head who cant resist a p**s take

Thanks.

Great web site as well Craig


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