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01-20-2012, 12:13 AM   #256
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QuoteOriginally posted by liukaitc Quote
and nowadays APS-C DSLR is pretty sharp and high ISO is pretty good too..
I do not think people really need go to FF if ur prints are usually in small to medium size..
Agreed. But, I want a FF DSLR for some different reasons.
To name two, a large viewfinder and more wide angle lens choices would be welcome.

And, yes, I do love shallow DOF. The OP wasn't diplomatic, but he was correct: Some full frame shots have a look that I'm unable to duplicate with my K-7.


Last edited by .a.t.; 06-29-2012 at 10:37 PM. Reason: fleshiness
01-20-2012, 09:17 AM   #257
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QuoteOriginally posted by all thumbs Quote
And, yes, I do love shallow DOF. The OP wasn't diplomatic, but he was correct: Some full frame shots have a look that I'm unable to duplicate with my K-7.
That's because they hold onto the k-mount which is designed for FF.
The aps-c use a smaller mirror so the register can be smaller which would make it easier to design faster and wider lenses.

So instead of going FF pentax could also go smaller with their APS-C camera's and get the same effect, i wonder how many would like that
01-20-2012, 12:21 PM   #258
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QuoteOriginally posted by Anvh Quote
That's because they hold onto the k-mount which is designed for FF.
The aps-c use a smaller mirror so the register can be smaller which would make it easier to design faster and wider lenses.

So instead of going FF pentax could also go smaller with their APS-C camera's and get the same effect, i wonder how many would like that
We know that FF works fine with a register of 28mm (cf Leica) and HF / APS-C works fine at 18mm (cf Sony NEX) and those numbers mean that lenses down to those focal lengths can be built without retrofocus elements. Anyone want a fast pancake 18?

But native lenses with longer focal lengths would need telephoto elements to avoid bulkiness and such will slow them down. I have an Enna Tele-Sandmar 100/4.5 made for Argus C3 (register= ~35mm; adapted to PK) that is just minuscule: 44mm long, 42mm wide, 110g. Compare that to a SuperTak 55/2: 38mm long, 58mm diameter, 200g. So tiny! And so slow. Faster longer lenses would necessarily be bigger and heavier, right?
01-20-2012, 01:06 PM   #259
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QuoteOriginally posted by Anvh Quote
...The aps-c use a smaller mirror so the register can be smaller which would make it easier to design faster and wider lenses.
I did some googling, but I'm still fuzzy on this. Could you elaborate about the lens design, please?


QuoteOriginally posted by RioRico Quote
We know that FF works fine with a register of 28mm (cf Leica) and HF / APS-C works fine at 18mm (cf Sony NEX) and those numbers mean that lenses down to those focal lengths can be built without retrofocus elements. Anyone want a fast pancake 18?
Does such a lens exist?

01-20-2012, 01:31 PM   #260
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QuoteQuote:
Does such a lens exist?
In lens design as in anything else... until you build it, you don't know how good it's going to be. With all this stuff about the advantages of full frame... I'm betting my DA*60-250 is lighter and smaller than it would have to be if it was a full frame lens. Not to mention all the times when you would have to crop your image with a full frame when you can frame to taste in a crop sensor. My lens with a 1.7 teleconverter gives me the equivalent of a 600 mm FF camera. What do I have do to get a 600 mm 6.7 FF lens... I have to carry a ton of extra glass. The simple fact is a lot of the time you will have added a lot of extra weight for no real advantage, and for a very real disadvantage. The whole argument for FF is that for some reason, you need the extra surface area. Meanwhile simple logic would dictate that a 50 mm image on an FF camera is exactly the same as the full frame image.. there is just less of it. It seems to me people have taken a lot of time and effort to try and prove there is some kind of difference... but apart from the less of it thing, I'm not seeing it. Meanwhile, there's been some horrible images posted on the "look" and the first thing that comes to mind is "dude, did anyone ever tell you net to have the foreground out of focus, it's distracting and annoying. If the look is real bad photography, please. Sure, it's great when it works.

So let be benevolent and assume that by going to an equivalent lens at 35mm on a cropped sensor the image we be different. And the point I would make they would be, different, not necessarily better.

I see all these people crying for FF, and I sit here and think why? All the things I read make me go "huh", because they might be true... but they also might not be true. I don't see how you can approach these issues from a theoretical perspective. Do you really think you'd be a better photographer shooting FF over a crop sensor? Ask me where my Mamiya 645 is. Weight, expense of lenses and the lack of choice in terms of the lenses available did it in.
01-20-2012, 01:35 PM   #261
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QuoteOriginally posted by all thumbs Quote
QuoteOriginally posted by RioRico:
We know that FF works fine with a register of 28mm (cf Leica) and HF / APS-C works fine at 18mm (cf Sony NEX) and those numbers mean that lenses down to those focal lengths can be built without retrofocus elements. Anyone want a fast pancake 18?
Does such a lens exist?
Dunno, I haven't looked at NEX offerings lately. But it should be feasible.
01-20-2012, 03:31 PM   #262
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QuoteOriginally posted by RioRico Quote
Dunno, I haven't looked at NEX offerings lately. But it should be feasible.
Sony makes a small 16 f/2.8 for the NEX.
Sony E 16mm f/2.8 (Sony NEX) - Review / Lens Test Report

Last edited by .a.t.; 01-20-2012 at 05:02 PM.
01-20-2012, 05:49 PM - 1 Like   #263
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QuoteOriginally posted by all thumbs Quote
I did some googling, but I'm still fuzzy on this. Could you elaborate about the lens design, please?

Does such a lens exist?
Fuji XPro1 has an 18/2 lens that looks pretty much "pancake" to me. Check the photos from the press releases. They should give you a good idea of the lens design achievements mentioned by Anvh.



BTW, since this thread is about FF and APS-C, here is another potential issue with FF sensors (regular CMOS ones):

An Open Letter To The Major Camera Manufacturers

Might explain why I don't see a huge difference between 1.2 and 1.4 lenses. I am wondering if this could also impact coma.

01-20-2012, 06:11 PM - 1 Like   #264
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QuoteOriginally posted by RioRico Quote
We know that FF works fine with a register of 28mm (cf Leica) and HF / APS-C works fine at 18mm (cf Sony NEX) and those numbers mean that lenses down to those focal lengths can be built without retrofocus elements. Anyone want a fast pancake 18?
Yeah but i don't want a mirrorless though.
30mm looks to be doable for APS-C and that's perfect if you ask me.
Also the corner sharpness really hurts with such shallow registers...


QuoteOriginally posted by all thumbs Quote
I did some googling, but I'm still fuzzy on this. Could you elaborate about the lens design, please?
It's like Riorico said.
those numbers mean that lenses down to those focal lengths can be built without retrofocus elements

So basically when you've a 30mm register distance it means that becomes you "standard" so the easy design they use for 50mm lenses can be used to make 30mm lenses to say it simply.


What is the diameter of the k-mount? 44mm i believe.
So if they only changed the register a 30mm f/0.75 should theoretically be possible.
But it should be smarter to increase the mount diameter a bit as well to make it easier to design faster lenses.

The Q has real potential you know, i wonder why they didn't make a faster prime for it but who knows.
01-20-2012, 06:35 PM   #265
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QuoteOriginally posted by Laurentiu Cristofor Quote
Fuji XPro1 has an 18/2 lens that looks pretty much "pancake" to me. Check the photos from the press releases. They should give you a good idea of the lens design achievements mentioned by Anvh...
QuoteOriginally posted by Anvh Quote
It's like Riorico said.
those numbers mean that lenses down to those focal lengths can be built without retrofocus elements...

Very interesting. Thanks.
01-20-2012, 06:54 PM   #266
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QuoteOriginally posted by Anvh Quote
Yeah but i don't want a mirrorless though.
Oh, I have plenty of thin mirrorless cameras. They all take film, of course.

QuoteQuote:
Also the corner sharpness really hurts with such shallow registers...
So Leitz L39 lenses have bad corner sharpness? I hadn't noticed.

QuoteQuote:
But it should be smarter to increase the mount diameter a bit as well to make it easier to design faster lenses.
EOS is about the widest-throat mount in use, at 54mm. Sony-Minolta Alpha is ~50mm. NEX and OM are at 46mm, Nikon at 44mm, PK and NX at 42mm, and m4/3 at ~38mm. Does this explain all that faster Canon glass?
01-20-2012, 08:36 PM   #267
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ISO gain to account for CMOS T-stop inefficiency!

QuoteOriginally posted by Laurentiu Cristofor Quote

BTW, since this thread is about FF and APS-C, here is another potential issue with FF sensors (regular CMOS ones):

An Open Letter To The Major Camera Manufacturers

Might explain why I don't see a huge difference between 1.2 and 1.4 lenses. I am wondering if this could also impact coma.


I don't think I remember seeing that before, thanks for the link. (here's the updated link.)

Note that's CMOS sensors in general, not just FF ones. The sensors with the smallest pixel size showed the most light-loss, as well - good news for FF.

Also - look at the 5D classic in that top graph - a great platform to shoot f/1.2 lenses on! (which is one of the reasons I wanted to pick up a used $850 FF 5D body - shoot my K-mount Cosina 55 f/12. on it )

(Data mining can be almost a form of research at times, nice job DxO.)


"Raising ISO to compensate light loss
A further assessment is still more troubling. It seems that many camera makers are raising the ISO sensitivity when the lens opening is at its widest, probably to cover up the lack of efficiency. “We have ascertained,” explained Guichard, “that on many cameras, the ISO is pushed up on the order of 1/3 to 1/2 stop when the lens opening comes close to its upper limit
."








.

Last edited by jsherman999; 01-20-2012 at 08:43 PM.
01-21-2012, 12:23 PM   #268
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QuoteOriginally posted by RioRico Quote
Oh, I have plenty of thin mirrorless cameras. They all take film, of course.

So Leitz L39 lenses have bad corner sharpness? I hadn't noticed.

EOS is about the widest-throat mount in use, at 54mm. Sony-Minolta Alpha is ~50mm. NEX and OM are at 46mm, Nikon at 44mm, PK and NX at 42mm, and m4/3 at ~38mm. Does this explain all that faster Canon glass?
Was talking about the NEX with the first two, non of their lenses really gives a good corner sharpness with that short register.
Digital sensor likes to have the light hit them so straight as possible, and as you can see the shorter the register becomes the sharper the angle becomes at the corners so it isn't good for the image quality.
Besides how much do you gain when you make the register that small... I really think 30mm and a mirror is the way to go for APS-C but hey who am i?

Ricoh is one of the first to make a good digital camera for the Leica M mount, quite an achievement no idea how they have done it though.
(looks like they use a special mirco lenses design infront of the sensor.)



Well yes for a part, if the diameter of the mount is larger it means the opening of the lens can also be larger, very simple right.
01-21-2012, 11:27 PM   #269
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QuoteOriginally posted by Anvh Quote
Digital sensor likes to have the light hit them so straight as possible, and as you can see the shorter the register becomes the sharper the angle becomes at the corners so it isn't good for the image quality.
I know Leica worked hard to address this issue in their M9 camera by custom designing the sensor, but I expect the problem becomes worse the larger the sensor is, so APS-C ones may actually hit a good compromise spot here. Maybe that's one more reason (secondary though) why Fuji preferred to pick an APS-C sensor for their XPro1?

Also, is this problem really solved much better by longer registration distances (the LL article suggests there are still issues)?
01-22-2012, 04:45 AM   #270
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QuoteOriginally posted by Laurentiu Cristofor Quote
I know Leica worked hard to address this issue in their M9 camera by custom designing the sensor, but I expect the problem becomes worse the larger the sensor is, so APS-C ones may actually hit a good compromise spot here. Maybe that's one more reason (secondary though) why Fuji preferred to pick an APS-C sensor for their XPro1?

Also, is this problem really solved much better by longer registration distances (the LL article suggests there are still issues)?
Leica uses a CCD sensor that allows for light to hit at more oblique angles that CMOS does. CMOS uses relatively deep wells, that the sensels sit at the bottom of. If you don't put a micro lens at the top of the wells, you lose any light that can't reach the bottom of the well.
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