Wish the Q2 came with a 35mm lens

[acg69]

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I am a big fan of the 35mm and I would have put up with the greater size/weight of a Summilux 35 on the Q. But that’s just me... Everyone has their own taste and shooting style, so a company needs to compromise. With the quality of the sensor and the lens on the Q2 you can crop to your heart’s delight, although I realize that it’s not the same as a true 35mm. At the end of the day, different setups work for different people and the Q2 (any Leica for that matter) is not a product to appeal to the masses; it is a niche product by definition and the question is which niche to appeal to. For me, it works and I am learning to shoot with the 28mm (harder than the 35mm imo) but I also keep an X100F on standby if I get the urge!

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[sfphoto]

1 hour ago, acg69 said:

...it’s not the same as a true 35mm...
...I am learning to shoot with the 28mm (harder than the 35mm imo)...

What exactly do you mean? You just have to set the crop to 35mm and you are done. OK, you "only" get 30MP, but otherwise exactly the same as a 35mm f/2 lens...

[jaapv]

 

5 minutes ago, sfphoto said:

What exactly do you mean? You just have to set the crop to 35mm and you are done. OK, you "only" get 30MP, but otherwise exactly the same as a 35mm f/2 lens...

Umm..  it is a 1.7 lens. Try it - exposure values don't change when you select the 35 mm framelines. Please don't fall for this "light gathering" baloney. The amount of light per square mm/ pixel will not change with cropping.

[sfphoto]

7 minutes ago, jaapv said:

 

Umm..  it is a 1.7 lens. Try it - exposure values don't change when you select the 35 mm framelines. Please don't fall for this "light gathering" baloney. The amount of light per square mm/ pixel will not change with cropping.

You are correct: The amount of light per pixel does not change when you crop. That's why I was writing: It is a 28mm f/1.7 lens; hence, when you crop you get the same image as if you used a 35mm f/2.125 lens in terms of light gathering and depth of field.

Edited March 5, 2020 by sfphoto

[jaapv]

Light gathering concerns the total amount that a lens system can collect, important for astronomical telescopes and wholly irrelevant for photography.  The maximum aperture of your 35 mm lens is still 1.7. 

[sfphoto]

5 minutes ago, jaapv said:

Light gathering concerns the total amount that a lens system can collect, important for astronomical telescopes and wholly irrelevant for photography.  The maximum aperture of your 35 mm lens is still 1.7. 

Light gathering depends on the lens AND the sensor. If you crop, you throw away light. The title of the thread is "Wish the Q2 came with a 35mm lens" and I was saying, if it was a 35mm f/2.1 lens you would be getting similar results to what you are already getting by simply cropping your 28mm f/1.7 lens. Of course, you do not have to adjust your exposure time when you crop.

[jaapv]

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No, you do not throw away light; the number of photons each pixel gathers is the same, you just use fewer pixels with the same illumination. This whole "light gathering" for photographic lenses is a weird internet invention. The difference in DOF is a totally different thing.

[sfphoto]

3 minutes ago, jaapv said:

No, you do not throw away light; the number of photons each pixel gathers is the same, you just use fewer pixels with the same illumination. This whole "light gathering" for photographic lenses is a weird internet invention. The difference in DOF is a totally different thing.

As I said, the exposure settings do not change (as the light intensity per pixel does not change). But you are throwing away all the light that falls onto the areas on your chip that you have cropped away. Hence, you are "wasting" some of the capabilities of your beautiful 28mm/1.7 lens. Therefore, it is important to understand that the cropping is not the same as if you had a full-frame 35mm/1.7 lens. Is is like having only a f/2.1 aperture (on a full frame chip).

This is all I have to say on this topic of light gathering. The most important point is that the 35mm crop looks exactly the same as a 35mm lens in terms of perspective, which is often misunderstood.

[jaapv]

We'll agree on the last bit then.

[pippy]

4 hours ago, sfphoto said:

As I said, the exposure settings do not change (as the light intensity per pixel does not change). But you are throwing away all the light that falls onto the areas on your chip that you have cropped away. Hence, you are "wasting" some of the capabilities of your beautiful 28mm/1.7 lens. Therefore, it is important to understand that the cropping is not the same as if you had a full-frame 35mm/1.7 lens. Is is like having only a f/2.1 aperture (on a full frame chip)...

If we are considering using any one lens on something like the x1.33 M8 and the full-frame M9 then no we wouldn't. All you lose is the image-area lost because of the area cropped-off by using the smaller chip. You do not lose or 'throw away' any light from the sensor area. The aperture is a constant as long as the distance between the rear nodal-point of the lens and the focal plane is a constant (Inverse Square Law of Light).

Think about it; if a 28mm f1.7 lens is used on a full-frame body (such as the M9) and the correct exposure requires an aperture of f1.7 to be set then putting the same lens on a smaller-chip body (such as the M8) and shooting it at f1.7 will not result in either over- nor under-exposure. It is still f1.7. On a 1.33 crop body such as the M8 it will be, in effect, a 37mm f1.7 lens.

The effective aperture would only change if the same lens was used on a camera with a different sized body-depth (due to the aforementioned Inverse Square Law of Light) but then the lens wouldn't be able to be used on both systems in the first place as their focussing parameters would not be compatible.

Philip.

Edited March 5, 2020 by pippy

[Ko.Fe.]

On 11/14/2019 at 8:39 PM, leicameech said:

This.

Spoke with the Leica rep about this, and there are a couple things: a 35mm lens would have been too big if it were also an f/1.7 or f/2 lens, which is what Q fans would expect, as it is a camera with a fixed, fast lens. The other way to achieve a 35mm or even 50mm Q (according to Leica rep, they considered both) would have been to make the lens without as wide of a max aperture value (i.e. somewhere in the f/3.4-4.5 range). The Q is able to focus quickly in part because of the focal length -- because the wider the lens, the wider the depth of field (at a given aperture and focal distance when compared to a longer lens at the same aperture and same focal distance). The lesser need for the elements to move long distances within the lens assembly (because at a certain point from focal distance to infinity will be in focus, and that point will occur closer to the focal plane than when using a longer focal length lens), the quicker it is able to focus without using extra motors (like the SL lenses). It just isn't moving as much on the inside as it would have to if it were a longer focal length.

If you've played with a Sony RX1Rii, their fixed-full-frame 35mm f/2 camera, you've noticed it doesn't focus as quickly as the Q. Apparently (I'm not an engineer), that's exactly why Leica won't make a 35mm or 50mm Q. In order to keep the Q size, a compromise must be made. And that compromise would either be the size of the lens (would have to be bigger) or the aperture (would have to be slower). 

I missed this one.

If I recall it correct the wider lens get under Leica the bigger it is. 21 Lux is a monster, 28 Lux isn't far from it, but 35 FLE isn't this big.

The focal length and focus speed is good theory for plastic film P&S. With wide lenses they have close and else focus modes. With more advanced lenses it is irrelevant.

I had Canon 50 1.2L and still have L zooms, they are made for sports, BIF and they focus instantly. On correct cameras :). Canon has 50mm 1.2 RF L lens now R series camera. Those are like Q series. EVF, FF. It is fast to focus.

Q(2) with 28 1.7 is already disproportional camera. Lens is big, IMO. While with high ISO and IS same (in practical photography) results are achievable with much compact 28 f2.8 lens. 

And as I mentioned before, Q-X. If Leica made X and X Vario, why no Q with 28 or 35, 50? Even Sigma did it. Some of their cameras are on waiting list. 

 

 

[sfphoto]

3 minutes ago, pippy said:

No it isn't. All you lose is the image-area lost because of the area cropped-off by using the smaller chip. You do not lose or 'throw away' any light from the sensor area. The aperture is a constant as long as the distance between the rear nodal-point of the lens and the focal plane is a constant.

Think about it; if a 28mm f1.7 lens is used on a full-frame body and the correct exposure requires an aperture of f1.7 to be set then putting the same lens on a smaller-chip body and shooting it at f1.7 will not result in either over- nor under-exposure. On a 1.33 crop body such as the M8.2 it will be, in effect, a 37mm f1.7 lens.

Philip.

You are absolutely correct. The label on the lens and the exposure setting on your camera do not change. But that was not the question. You can crop to "400mm f/1.7" if you want. But you do not get the same image as if you had a true 400mm/1.7 lens.

With the matching lens you are getting more light onto a smaller chip (but the pixels might also be smaller). The specific ISO settings take care of all this so that you expose correctly if e.g. you were using an external light meter.

I had thought about the original question of the pros and cons of cropping to 35mm on a Q2. I argued that this is perfectly doable. And IF you were looking for a lens that gave you the same perspective and DOF on the full frame, it would be a 35mm f/2.1. And in this case the image would indeed be darker because you are magnifying the same area as before onto the whole chip. Ever used a teleconverter? 

I found this video that illustrates some of what I explained: https://www.youtube.com/watch?v=f5zN6NVx-hY

 

 

[pippy]

36 minutes ago, sfphoto said:

Ever used a teleconverter?

 

If we ignore covering-power / vignetting for a moment if a full-size sensor is being used and the correct exposure requires f1.7 and the lens is set to f1.7 then every pixel will receive an exposure of f1.7. If we are using a 50mm f1.7 lens the pixels will be receiving f1.7 amount of light. If we put this lens on a x1.33 crop-sensor body then each pixel still receives f1.7 light. If we put on a 400mm f1.7 lens and shoot wide-open the pixels will still receive f1.7 amount of light. If we go back to the 50mm image and crop the buggery out of it so we are only using a central 2mm square area of the sensor then the pixels we see will still have received f1.7 worth of light.

If we shoot on a 28mm lens and crop in to what would be effectively a 400mm lens section of the image we will see a resultant loss of IQ but there will have been absolutely not the slightest change in the amount of light received by the pixels. Otherwise the overall result would be uselessly uneven exposure of every frame ever shot!

Shoot a white wall to get 18% grey image. The edges are 18% grey. The mid-points between the edge and centre are 18% grey. The centre is 18% grey. Full-frame crop the tone is 18% grey. 500% crop the tone is 18% grey.

Using a teleconverter is a completely different matter because of - once more - the aforementioned Inverse Square Law of light.

Placing a teleconverter between the rear nodal-point of a lens and the focal plane increases this distance therefore the intensity of light reduces as a square of the  distance travelled. Doubling the the lens-to-film-plane distance reduces the light intensity to 1/4 the original amount therefore two stops need to be allowed for this difference. Tripling...by 1/9th...and so on.

Or are you talking about something else?

Philip.

 

 

 

Edited March 5, 2020 by pippy

[sfphoto]

4 minutes ago, pippy said:

If we ignore covering-power / vignetting for a moment if a full-size sensor is being used and the correct exposure requires f1.7 and the lens is set to f1.7 then every pixel will receive an exposure of f1.7. If we are using a 50mm f1.7 lens the pixels will be receiving f1.7 amount of light. If we put on a 400mm f1.7 lens and shoot wide-open the pixels will receive f1.7 amount of light. If we go back to the 50mm image and crop the buggery out of it so we are only using a central 2mm square area of the sensor then the will have received f1.7 worth of light.

If we shoot on a 28mm lens and crop in to what would be effectively a 400mm lens section of the image we will see a resultant loss of IQ but there will have been absolutely not the slightest change in the amount of light received by the pixels. Otherwise the overall result would be uselessly uneven exposure of every frame ever shot!

Shoot a white wall to get 18% grey image. The edges are 18% grey. The mid-points between the edge and centre are 18% grey. The centre is 18% grey. Full-frame crop the tone is 18% grey. 500% crop the tone is 18% grey.

Or are you talking about something else?

No. You are absolutely right. Exactly, what I said: The exposure settings do not change when cropping. It is like cropping in LR or PS.

But as the IQ goes down you may wonder if you would rather like to have a 35mm, 50mm or 400mm lens. And I said that you have to multiply the aperture with the crop factor to get a sense of which lens would deliver equivalent FOV and DOF. And in the case of the 35mm crop on the Q2 it would be a 35mm/2.1.

This was an attempt to address the OP's point: Would we be happy with a Q2 with 30MP and a 35mm/2.1 lens? For me the answer is "yes" (and I already have this in my Q2).

[pippy]

8 minutes ago, sfphoto said:

...as the IQ goes down you may wonder if you would rather like to have a 35mm, 50mm or 400mm lens. And I said that you have to multiply the aperture with the crop factor to get a sense of which lens would deliver equivalent FOV and DOF. And in the case of the 35mm crop on the Q2 it would be a 35mm/2.1.

OK. Thanks for explaining your meaning (even) more fully. I see now we were talking at slightly cross-purposes.

Regards!

Philip.

Edited March 5, 2020 by pippy

[Leica28]

I prefer the 28mm over a potential 35mm focal length.

[hdmesa]

Cropped Q2 is a CL on steroids – better IQ in the cropped output since you're using a lens designed to cover a larger sensor. The images I get from even the original Q cropped to 35 and 50 at f/1.7 look amazing to me.

[Guest]

In my view if you dislike the 28mm lens you will not buy the Q2 despite all the digital zoom arguments.

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Hallo,

Look here: Leica Q

[acg69]

21 hours ago, sfphoto said:

What exactly do you mean? You just have to set the crop to 35mm and you are done. OK, you "only" get 30MP, but otherwise exactly the same as a 35mm f/2 lens...

It’s not the same. This issue has been discussed ad nauseam here and all over the internet. If you use the digital zoom to go to 70 mm for example, you do not get the same image you would get if you shot with a 70 mm lens. You just get a cropped version of the image shot with a wide angle lens. In any case, obviously the effect is not the same when you are just cropping to 35 since it is a lot closer to the 28, but still, it is not a true 35.

[sfphoto]

1 hour ago, acg69 said:

It’s not the same. This issue has been discussed ad nauseam here and all over the internet. If you use the digital zoom to go to 70 mm for example, you do not get the same image you would get if you shot with a 70 mm lens. You just get a cropped version of the image shot with a wide angle lens. In any case, obviously the effect is not the same when you are just cropping to 35 since it is a lot closer to the 28, but still, it is not a true 35.

Why is it not the same? Please explain.