Richard Butler

Richard Butler

DPReview Administrator
Lives in United Kingdom Seattle, United Kingdom
Joined on Nov 7, 2007

Comments

Total: 5449, showing: 961 – 980
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On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

chri1sm1x: Was APS-C designed to have a crop factor that meant classic focal lengths became equivalent to other classics? 85mm when used on APS-C becomes [nigh on] 135mm, or is that just a coincidence?

That's a really good question. I don't know the answer, I'm afraid. It's something I've often thought about looking up.

Link | Posted on Feb 20, 2017 at 18:18 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

Ok, let's take it back to brass tacks:

Just as equivalent focal lengths tell you the angle of view of one system relative to another, equivalent f-numbers tell you about the *effect* of the aperture size, relative to another system.

However, because F-numbers and ISO are based around light-per-unit area, not total light, equivalence is not necessarily helpful for setting exposure.

So you can either ignore equivalence and just think that larger sensor cameras are somehow less noisy and can offer shallower depth-of-field, or you can try thinking in terms of equivalent apertures and understand how much of a difference there is between systems, so that you can fully understand the size/price/IQ balance each one strikes.

Link | Posted on Feb 20, 2017 at 18:11 UTC
On article The effect of pixel size on noise (113 comments in total)
In reply to:

RichardRE: What about a 4/3rds camera as in the Panasonic lx100 with 16mp sensor but only using 13 mp?

Using a crop of a sensor is identical to using a smaller sensor.

So although the individual pixels in an LX100 perform indentically to any other camera that uses all 16 million pixels, its overall image quality will be lower, when compared at the same print/viewing size. And it'll be lower in exact proportion to the degree to which it's cropped.

So, rather than being a 224 sqmm sensor, it effectively has only a 180 sqmm sensor and the light gather capability that goes with that.

Link | Posted on Feb 20, 2017 at 01:41 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

A 4.5mm aperture diameter in that 200mm lens would be an F44 aperture. It would project one quart as much light over every square mm of sensor but you are capturing/measuring light on 4x the number of square mm.

Consequently, you can look at it two ways:

You could increase the exposure time on the full frame camera and conclude the full frame camera is less noisy at the same ISO.

Or you could keep the shutter speed the same, use a higher ISO and note that you've got two images which are virtually identical (D-O-F, diffraction, noise), except for the ISO rating.

If you're not satisfied with the examples in the article and you have access to both a full frame and a Micro Four Thirds camera, then send me a private message and we can discuss ways for you to test this to your own satisfaction.

Just to be clear, I'm not suggesting that, day-to-day, you change the way you shoot either camera, I'm just saying that it helps you understand their relative strengths.

Link | Posted on Feb 20, 2017 at 01:36 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

Thanks for the apology, it's appreciated.

As I say, the way we think about exposure (F-numbers and ISO, specifically) is designed to ensure that you don't notice any difference in exposure between your two systems. I'm not arguing against that or proposing that equivalence should be used in its place.

However, when you shoot at F22 on a Micro Four Thirds camera, you are shooting not at F44 but at the *equivalent of* F44. You'll get the same depth-of-field, and diffraction and very similar noise characteristics as shooting F44 on your full frame camera.

Let's, assume you're talking about a 100mm lens. F22 would be a 4.5mm aperture diameter. If you set up your full frame camera in the same spot, then you'd need a 200mm lens to give the same framing (putting to one side the 3:2/4:3 aspect ratio difference).

Link | Posted on Feb 20, 2017 at 01:30 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

In which case, I'd recommend recalibrating it. Perhaps by *testing* the principles explained here.

Looking at photography in terms of total light, rather than the light per unit area approach (that is necessary for the same exposure rules to work across different film formats/sensor sizes), may seem antithetical and alien, but that doesn't mean it's untrue.

Nobody is proposing that 'total light' be used to set exposure, however, it does provide a useful way to compare the performance evelopes of different formats.

Look at the examples in the examples in the article, try for yourself. It may not 'feel' right, but it stands up to scrutiny, both logically amd practically.

Link | Posted on Feb 19, 2017 at 20:18 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

Two lenses of the same F-number project the same amount of light per unit area (this is easiest to recognise if you imagine them all being pointed at the same, evenly illuminated panel).

So, if you reduce the F-number by two stops, you get 1/4 as much light *per unit area*. However, if you then use a sensor with 4x the area, then you end up capturing the same amount of light in total.

Yes, the ISO rating is different but that's because the ISO number, *by definition* relates light per unit area to final image brightness. This disguises the reason that the two images, taken with *equivalent* apertures and the same shutter speed, will have the same depth-of-field, the same amount of diffraction and very similar noise levels, when viewed at the same size. (Because both sensors had access to the same amount of light).

The article has real-world examples showing this to be the case.

Link | Posted on Feb 19, 2017 at 18:57 UTC
On article Fujifilm XF 23mm F2 R WR sample gallery (285 comments in total)
In reply to:

MistaHaid: who needs such an ultra wideangle? Why not 35mm or 50mm?

It's an APS-C lens. 35mm equivalent isn't an ultrawide.

Link | Posted on Feb 16, 2017 at 22:39 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

Miki Nemeth: I was able to download the ZIP file but it doesn't open: my 16G i7 Surface Pro 4 computer says Compressed Zipped Folder Error. Has anyone managed to download it and opened it?

We're re-uploaded an uncompressed version, so please try again,

Link | Posted on Feb 15, 2017 at 19:51 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

MadCypher: I've downloaded the ProRes file twice and I'm getting an extract error both times. Please fix the zip file. Thanks.

I'll check it and try to re-upload it tomorrow if the problem is with the file.

Link | Posted on Feb 15, 2017 at 01:08 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

BJN: Choppy pan, what shutter speed?

I did say that poor technique was a possible cause. I was trying to pan quickly enough to show any rolling shutter present but not so quickly as to be ridiculous. Seems I should have gone a tad slower, still (or shot at a higher frame rate).

Link | Posted on Feb 14, 2017 at 17:32 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

FuhTeng: Yes, I know you guys at DPR have to deal with the trolls and lunatics on this site, but man, stuff like this makes me think you guys have a pretty sweet job anyway.

I'm not sure the result would be this coherent if I had. But I'll admit I did reward myself with a small dram when I got home on Sunday night.

Link | Posted on Feb 14, 2017 at 16:58 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

FuhTeng: Yes, I know you guys at DPR have to deal with the trolls and lunatics on this site, but man, stuff like this makes me think you guys have a pretty sweet job anyway.

It's true, we do. But what the video doesn't show is how much of my weekend was spent editing this together. ;)

Link | Posted on Feb 14, 2017 at 02:54 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

BJN: Choppy pan, what shutter speed?

At the start? 1/50th of a second. Don't discount the possibility of poor technique and a less-than-perfect tripod head.

Link | Posted on Feb 13, 2017 at 23:51 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

Dhonchak: Hey ! amazing footage , i have some question and it will be very helpful if you could help me.

Q.1 - How is the autofocus during the video compared to g85 and especially canon 80d. is it good enough to be used as a daily vlogging camera.

Q.2 - what is the crop factor when dual IS is turned on ( in both 1080p and 4k)

Q.3 - will it vignette with a sigma 18-35 + speedbooster XL without IS on(since it doesnt crop without IS on)?

Q-4 - when will the V90 cards be available to allow for 400mbps 4k internal recording?

Panther Fan is correct: there's an additional crop when you add E stabilization. It's a small crop but I'll measure it when I'm back in the office, tomorrow.

Link | Posted on Feb 13, 2017 at 21:43 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

Dhonchak: Hey ! amazing footage , i have some question and it will be very helpful if you could help me.

Q.1 - How is the autofocus during the video compared to g85 and especially canon 80d. is it good enough to be used as a daily vlogging camera.

Q.2 - what is the crop factor when dual IS is turned on ( in both 1080p and 4k)

Q.3 - will it vignette with a sigma 18-35 + speedbooster XL without IS on(since it doesnt crop without IS on)?

Q-4 - when will the V90 cards be available to allow for 400mbps 4k internal recording?

Q2 - I'm not seeing any crop when I turn on Dual IS (I'll check more, when I get a moment.

Q4 - I think V90 cards have been announced but the furmware bringing 400 mbps output isn't coming until 'summer.'

Link | Posted on Feb 13, 2017 at 21:05 UTC
On article Panasonic Lumix DC-GH5 sample footage (81 comments in total)
In reply to:

John Koch: DPR: please expand your notes or explanations. Whoever took the shots obviously knew the camera far better than any green box-opener. Was a Panasonic crew responsible? Were all shots hand-held? Which lens? Dual IBIS-OIS? How was the (perfect!) audio recorded? A separate recorder altogether? Was an external shotgun mic suspended over the speaker? Or was there an mini mic hidden under his cap? Ambient light only? Grading in post? What LUT?

It was all hand-held and almost everything was shot with the 12-60mm F2.8-4.0, meaning there was Dual IS.

Ambient lighting only and minimal grading. One camera was shot in Cinelike D, so it was mainly a case of pulling the blacks down a fraction. The close-up drift around the three Peat Week bottles at the end may be the 12mm F1.4 and was color graded with a single by-eye colour correction to stop the change of White Balance being too jarring.

Let me know if you have any other questions.

Link | Posted on Feb 13, 2017 at 19:58 UTC
In reply to:

DarnGoodPhotos: Isn't this the sensor they are working on with Fujifilm?

Dr_Jon: *this* is also a CMOS sensor with an organic layer on top, allowing global shutter, it just happens to be sensitive to both visible and NIR light.

Link | Posted on Feb 10, 2017 at 20:59 UTC
On article What is equivalence and why should I care? (2469 comments in total)
In reply to:

amblepath: I fall into the more depth of field is an advantage most of the time camp. I know it's hard to accept for some that less depth of field to many is a con and yet it truly is. With m4/3 for instance you get to keep the quick shutter speed of the widest aperture and still keep vital areas in focus. Software also is getting better and better for blurring backgrounds if you need more. This leaves high ISO noise as the only con for me from smaller sensors like m4/3 and APS-C. So if the best in high ISO is your need then it's full frame for you. Otherwise remember more depth of field for your average photographer is often, possibly even mostly a pro not a con.

If you shoot at, say, F5.6 on a Micro Four Thirds camera, then there's no reason you can't shoot at F11 and the same shutter speed on a full frame camera. You need to raise the ISO but, since you're capturing the same amount of total light, the two images will look very similar, unless there's a radical difference in sensor performance.

The only point at which one system has 'more depth of field' is once you've stopped the larger sensor camera down to its minimum aperture. And that usually means getting well into diffraction-limited territory.

Link | Posted on Feb 10, 2017 at 20:57 UTC
In reply to:

phips243: Why isn't Fujifilm mentioned? It's pretty clear that the organic film was developed by them...

The two companies were working together at some point. The absence of any mention in Panasonic's press release (or any press release from Fujifilm) suggests this particular piece of work isn't direct fruit of that collaboration (perhaps because the breakthrough here is the control of the two layers, not the layers themselves).

Link | Posted on Feb 9, 2017 at 21:41 UTC
Total: 5449, showing: 961 – 980
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