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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Making everyone happy with Scarlet Lenses

Glazarus said:
Have you ever used a EF-S lens? 18mm is 18mm, because the rear end of the lens is further into the camera to adjust the image because of the smaller sensor. It was created so that superwides could be used on DSLR's.
As I see it, if the mount is closer to the sensor it should make the crop less then it is. Maybe not entirely but it could get down to 1.6 at least.
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I'm not sure if this is true. An 18mm EF-S lens is 18mm yes. But if you put it on a Digital Rebel body with a 1.6x APS-C sensor it'll have a 29mm field of view. Shortening the FFL makes the field of view a bit wider and increases image quality for wide angle lenses. But it doesn't give you full 35mm field of view on a smaller sensor. And it is supposed to only make a difference in wide angles. Check out dpreview.com where they review the EF-S 18-55mm lens. They list it's 35mm equivalent field of view as 29-88mm.

Also, designing this for scarlet would be tough. The EF-S lenses were built in a specific way to extend the rear element closer to the sensor. If one were to simply move a Nikon lens closer to scarlet's sensor it'd just throw back-focus off and keep you from being able to focus on close-up objects. Adding something like that to an existing lens would probably cost more than buying this camera.

That's my understanding. If I'm wrong, let me know. And if you have pictures taken with an 18mm EF-S lens that show it to have the equivalent field of view of an 18mm lens on a 35mm camera please post them.
davide
 
mounting it closer to the sensor would completely mess up focus
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Yes, I'm aware of that, but you could do some math if you need to calculate distance from the camera etc. Just adjust the numbers based on the distance.
The main thing is that the crop is so huge that it's hard to get any good wide images at all. It's like we are left out with nothing but long lenses when having interchangebles.

So, either, the mount must compensate for the large cropping or they create a real good wide to normal/tele zoom that is already adjusted so you get a good wide range.
 
Glazarus said:
Have you ever used a EF-S lens?
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Yes, I own a Digital Rebel XT. Do you have access to an EF-S lens and an EF lens that can both zoom to close to the same milimeter focal length? If so, try switching between these, and you will see that the field of view is the same.

The EF-S mount was created for one reason: to mechanically make it impossible to put an EF-S lens on an EF camera. This allowed Canon to make lenses that do not meet the requirements of EF cameras in these ways:
1) The EF-S lenses are allowed to extend inside the camera so far that the larger EF mirror would hit it.
2) The image circle created by the EF-S lens doesn't have to cover the full 35mm frame.
The mount does nothing optically, but by allowing the above loosening of the requirements, they could make affordable wide-angle lenses for the smaller sensors.
 
For the love of all that's sacred and holy

For the love of all that's sacred and holy

Why won't you let them sell you a cheap camera? WHY?!:ranting2:

FFL points were interesting, btw. But all this sort of mod option would do is drive the price up who knows how much. It will, and should, be fixed glass on this little suckah. I've got a lot of Nikon sitting around and it'll go where it should - in front of a 35mm chip.
 
Chris Newman said:
Yes, I own a Digital Rebel XT. Do you have access to an EF-S lens and an EF lens that can both zoom to close to the same milimeter focal length? If so, try switching between these, and you will see that the field of view is the same.

The EF-S mount was created for one reason: to mechanically make it impossible to put an EF-S lens on an EF camera. This allowed Canon to make lenses that do not meet the requirements of EF cameras in these ways:
1) The EF-S lenses are allowed to extend inside the camera so far that the larger EF mirror would hit it.
2) The image circle created by the EF-S lens doesn't have to cover the full 35mm frame.
The mount does nothing optically, but by allowing the above loosening of the requirements, they could make affordable wide-angle lenses for the smaller sensors.
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Nice post Chris, people just can't seem to understand that 18mm is 18mm. Point number 2 is the critical thing - if your lens creates a circle big enough to cover the sensor then you can use it as long as you can get the sensor at the correct distance from the lens to focus the image.

So if you shoot with the same camera i.e. RED with its s35/APS-C (APS-C is the designation for the sensor size on cameras like the REBEL XT, EOS40D, etc. and is almost identical to the RED) no matter if you take a lens designed for a tiny sensor or large 4x5 film, (as long as you can position it so if focuses) if it is an 85mm it will look the same on the RED i.e a moderate telephoto.
 
Canasian I kind of agree with what you're saying.

The HV20 / HV30's from Canon are essentially fixed lens "out of the box" cameras but it is possible to remove the lens and mount other lenses via an after market 35mm adapter (if you feel the need to).

Therefore I couldn't see why in principle this couldn't be made possible with Scarlett as its obviously cheap to enable, although personally I have no desire for an interchangeable lens.

However, as I've posted elsewhere, I do see this as a possible solution to satisfying both potential camps of users. Stick an ultra high quality do anything zoom in the box a la XH-A1 and then make available the option for those who desire ultra wide or primes or other specialist lenses to use adapters to fit their own preferred lens. That way there's something for everyone.
 
chuck colburn said:
You want to talk about depth of field? lol
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Yes. Can anyone tell me what camera has the BEST depth of field? I have a small canon handycam style thing and it has very BAD depth of field. I want to make the depth of field better because i want it to be like in teh movieezzzz..


</sarcasm>
 
Alsone said:
The HV20 / HV30's from Canon are essentially fixed lens "out of the box" cameras but it is possible to remove the lens and mount other lenses via an after market 35mm adapter (if you feel the need to).
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You don't remove the lens, you attach the 35mm adapter in front of it.
 
karapetkov said:
You don't remove the lens, you attach the 35mm adapter in front of it.
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Yes, that's correct. An aux. optical group which attaches to the front of an imaging lens fixed or otherwise is sometimes referd to as an afocal lens. They can be positive or negative in focale length. They most often are single or doublet in construction but can be more complex particularly if negative in focale length.

This is similar to what we use on our night vision goggles.

http://www.nightoptics.com/pc/NO-NA-M3X/NightVisionScopes/3X+MS+Afocal+Lens.html

Here's another use for an afocal optical device.

http://www.stargazing.net/david/Nikon990/afocalcoupling.html
 
"Cheap / Good / Fast"

"Cheap / Good / Fast"

Ed Blythe said:
Why won't you let them sell you a cheap camera? WHY?!:ranting2:
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Sounds like the old "Cheap / Good / Fast" conundrum.
"They" want all three.
:whistling:
 
AquaVideoRed206 said:
Nice post Chris, people just can't seem to understand that 18mm is 18mm. Point number 2 is the critical thing - if your lens creates a circle big enough to cover the sensor then you can use it as long as you can get the sensor at the correct distance from the lens to focus the image.

So if you shoot with the same camera i.e. RED with its s35/APS-C (APS-C is the designation for the sensor size on cameras like the REBEL XT, EOS40D, etc. and is almost identical to the RED) no matter if you take a lens designed for a tiny sensor or large 4x5 film, (as long as you can position it so if focuses) if it is an 85mm it will look the same on the RED i.e a moderate telephoto.
Click to expand...

Yes an 18mm is an 18mm. And if you put a regular Canon EF 18mm or an EF-S 18mm lens on an APS-C type body you'll get the same field of view.

I think you're misinterpreting Point 2 by Chris. The point of the rear element extending backward is to make it possible to fit a small wide angle lens on an slr. Wide angle lenses are huge in SLRS versus rangefinder cameras because of the long flange focal length of SLRS. Rangefinder wide angle lenses can sit mostly inside the camera because there is no mirror that flips up that would hit them. Because an SLR wide angle lens is constrained to be far away from the film plane they are designed to be retrofocus, i.e. they are like reverse telephoto lenses.

This design helps eliminate fall-off and vignetting but it also makes for very large lenses. To allow for smaller wide angle lenses Canon designed EF-S to move the rear element closer to the film plane like rangefinder cameras. The point is NOT to get the same field of view with the same focal length as on 35mm. The EF-S 18-55 still gives the field of view of 29-88mm (according to the Canon website, link below). The point is to allow for a small wide angle lens. Yes, being closer to the film plane improves clarity on the wide angle side of EF-S zooms most tests find, but it doesn't give you 35mm field of view.

Don't believe me? Check out the Canon press release on EF-S lenses. Reducing size and weight is their explanation for using the EF-S design. Don't you think it'd be strange for them to leave out a feature as amazing as eliminating the crop factor on aps-c sized cameras?

http://www.canon-europe.com/for_hom.../zoom_lenses/ef-s_18-55mm_f-3.5-5.6/index.asp
 
Chris Newman said:
Yeah, we don't hear that very often from anybody around here.
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I don't have a problem admitting if I've got something wrong. There's no ego from me, just a genuine desire to take part in the discussion. :)
 
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