EV values in display?

Does the D7100 show the EV in the display somehow? Not by stops above or below exposure (like +1EV) but by absolute EV (such as EV 15 on a sunny day)? I know the camera knows what it is because thats how it figures out program priority settings. I broke my light meter and am debating wether or not to replace it. thanks for the help.

Jim

No. it displays as +-, not absolute

As far as I know, no modern camera displays the "EV" values. Only older manual cameras which had a CdS meter did so.

You actually do not need to display the EV. It can be easily calculated from the suggested ISO/Aperture/Exposure data.
Exposure value - Wikipedia, the free encyclopedia gives the formula. The article has a tables of EV, Aperture and exposure, for ISO 100.

Nobody asked, probably nobody cares, but technically, EV is only about the camera aperture / shutter speed combination (the dial settings), and its equivalent combinations. Camera settings of f/1.0 at 1 second is EV 0, regardless of ISO or exposure. Regardless if using ISO 100 or ISO 3200, f/1.0 and 1 second is still EV 0. EV is simply independent of ISO, and is not about any proper exposure... EV only about the actual numerical camera aperture/shutter setting combinations... the actual dial settings.

If we set the camera to say f/16 at 1/125 second, that is EV 15. Then leaving settings there, we can run ISO from the least value to its highest value, and it remains EV 15, at any ISO ... at any resulting exposure. EV is about the camera dial settings. +1 EV is a one stop step from those settings.

We do tend to say bright sunlight is about EV 15, then with the added implied meaning if at ISO 100, but ISO is not in the definition of EV. EV is specific camera settings (or equivalent), but if to suggest EV 15 is any specific exposure, then we have to specify at which ISO we imply.

Nikon does spec their metering range to be 0-20 EV, qualified to say at ISO 100, f/1.4, and 20 degrees C (I don't know why the temperature. )

What I had tried to convey is how to get the EV from the exposure settings of the camera. I do not think that EV is independent of the ISO.

If the camera shows 1 sec, F1.0 at ISO 100 then it is EV0. The camera exposure factors in the ISO set in the body, there is no way to uncouple it. My older Zenit displayed EV on the inbuilt meter. You just rotated the wheel till the pointer matched the needle. Then you read off the aperture/exposure combination off the dial. This was for ISO 100, and the manual explained how to modify it for other ISO - half the exposure for ISO 400, double for ISO 25 etc.

aroy said:

What I had tried to convey is how to get the EV from the exposure settings of the camera. I do not think that EV is independent of the ISO.

If the camera shows 1 sec, F1.0 at ISO 100 then it is EV0.

Click to expand...

The Wikipedia link you posted Exposure value - Wikipedia, the free encyclopedia says:

[h=2]EV as an indicator of camera settings[/h] EV corresponds simply to a combination of a shutter speed and an aperture setting, independent of any ISO setting—independent even of whether there is film in the camera or any light available.

WayneF said:

The Wikipedia link you posted Exposure value - Wikipedia, the free encyclopedia says:

EV as an indicator of camera settings

EV corresponds simply to a combination of a shutter speed and an aperture setting, independent of any ISO setting—independent even of whether there is film in the camera or any light available.

Click to expand...

Let me clarify.

EV is EV that is not disputed. Unless a camera has an exposure meter which shows the light values in EV, you have to depend on what the camera displays.

The camera display the Aperture-Shutter-ISO combination. That and only that. Change the ISO, the recommendation will change accordingly. What I had tried to convey is how to get the EV from what the camera displays.

The Aperture-Speed matrix is dependent on two more variables
a) The ambient light.
b) ISO which is the film/sensor sensitivity to light.

I hope that clarifies the matter.

NOTE.
1. Do not blindly rely on Wikipedia. It is written by mortals, and at times even reviewers miss out critical information (faux pax?). If in doubt to the veracity, I consult standard texts.

Exposure | Understanding Exposure - ISO, Aperture and Shutter Speed Explained
Exposure | Understanding Exposure - ISO, Aperture and Shutter Speed Explained, here is a quote "some uses do publish EV as if it refers to an illumination level at ISO 100".

aroy said:

The Aperture-Speed matrix is dependent on two more variables
a) The ambient light.
b) ISO which is the film/sensor sensitivity to light.

Click to expand...

You are speaking of exposure. The EV chart does not mention ISO or exposure. The EV chart is a different subject than exposure.

NOTE.
1. Do not blindly rely on Wikipedia. It is written by mortals, and at times even reviewers miss out critical information (faux pax?). If in doubt to the veracity, I consult standard texts.

Click to expand...

It is internet, but Wikipedia has the strong advantage of many readers/editors trying to keep it corrected. Bad stuff does not stand for long.

Most web pages have one single source, not correctable. Most are pretty good, but not every one of them knows what they are talking about. Anyone can put anything on the internet. Reader beware. Reading more to achieve a wider consensus is always good. But if short of time, Wikipedia is a good way to bet.

here is a quote "some uses do publish EV as if it refers to an illumination level at ISO 100".

Click to expand...

Yes, agreed, that is also what I said.

"but if to suggest EV 15 is any specific exposure, then we have to specify at which ISO we imply."

WayneF

"Nobody asked, probably nobody cares, but technically, EV is only about the camera aperture / shutter speed combination (the dial settings), and its equivalent combinations. Camera settings of f/1.0 at 1 second is EV 0, regardless of ISO or exposure. "

Not at all what i was taught in school. at EV15 ISO 100, you have to stop down the aperture and the speed in some combination of 15 stops. If ISO goes to 200 (1 stop) you have to take back a stop from either the aperture, shutter, or some equiv. combination. you can cipher the right exposure at any ISO without having to guess beyond the aperture/shutter figures.

Jim

aroy,

you are right, EV calculations do include ISO. EV0 being at ISO 100 F1.0 1sec, if the ISO number doubles, you have added one full stop to the exposure. ISO 100 to 200, or 1600 to 3200, one stop. this is exactly the trick to sports photography to increase shutter speeds to freeze action - in bright daylight, change ISO from 100 to 800 (adding 3 stops) and then take those 3 stops from your shutter speed to get pictures without motion blur.

WayneF,

EV is dependant on ISO. if you point your camera at a test subject on a bright day, in aperture priority mode, preferably on a tripod, you can change ISO in your camera by stops and watch those stops be taken from the shutter speed on your display. the charts you reference have a note on the bottom explaining ISO increases by stops result in EV being doubled.

Thanks for the replies. I gather the answer to my post is that my camera doesn't show the absolute EV even though the camera knows what it is. that's too bad, i can mentally figure out my manual settings the fastest that way. may have to get a new light meter after all.

thanks again,

Jim

jimalexander said:

WayneF

"Nobody asked, probably nobody cares, but technically, EV is only about the camera aperture / shutter speed combination (the dial settings), and its equivalent combinations. Camera settings of f/1.0 at 1 second is EV 0, regardless of ISO or exposure. "

Not at all what i was taught in school. at EV15 ISO 100, you have to stop down the aperture and the speed in some combination of 15 stops. If ISO goes to 200 (1 stop) you have to take back a stop from either the aperture, shutter, or some equiv. combination. you can cipher the right exposure at any ISO without having to guess beyond the aperture/shutter figures.

Jim

Click to expand...

See the EV chart I guess..

Doesn't the origin at f/1.0 at 1 second being numbered EV 0 sound extremely arbitrary? Convenient? What is it an exposure of? Even if you imagine it says ISO 100 (It doesn't mention ISO), what is it an exposure of? Rhetorical, but what is the theoretical origin of your notions of ISO 100?

You are close to the right idea with the concept of equivalent exposures. EV is in fact just a name for the set of shutter/aperture combinations which give an Equivalent Exposure. Not absolute, just relative. Not any one exposure, no ISO, just a name for the numerical set of equivalent shutter/aperture combinations.

If you increase shutter speed one stop, and open aperture one stop, that is still equivalent exposure at any ISO. If you only change one of them, that moves you to the next row. That's what the EV chart shows.

OK, you can pretend to arbitrarily assign an ISO, and then make claims for your new concept regarding exposures, so long as you always explain about your ISO. But ISO is not in the chart.

EV is really used to denote a specific shutter speed/aperture combination that yields an equivalent exposure for a given scene luminance. Some earlier hand held meters could be used measure in EV but it' not in widespread use any more. There are EV settings on the barrels of some of my oldest (1980's vintage) Hasselblad C lenses however.

The term "EV" is now used sometimes synonymously with f/ stop to denote a change in exposure setting from the "null" setting

You can always print this out on heavy card stock and laminate it. Cut out each ring and hold the two together with one of those clips with the two bendable "ears"


http://www.sakki.net/fileadmin/Sakki.net/Attachments/exposure-wheel.pdf

originally posted by WayneF

See the EV chart I guess..

Doesn't the origin at f/1.0 at 1 second being numbered EV 0 sound extremely arbitrary? Convenient? What is it an exposure of? Even if you imagine it says ISO 100 (It doesn't mention ISO), what is it an exposure of? Rhetorical, but what is the theoretical origin of your notions of ISO 100?

no argument that the chart can be used at the same ISO to compare different combinations of aperture and shutter that would give the same quantity of light (exposure). merely meant to point out that it is also expandable to be able to compare different combinations of aperture and shutter at different ISO, therefor it is not entirely independant of ISO such that one cannot say that EV15 is the same exposure value so that "we can run ISO from the least value to its highest value, and it remains EV 15, at any ISO ... at any resulting exposure." EV15 at ISO 800 has 3 components; aperture, shutter and ISO stops all totaling 15 stops.
You are close to the right idea with the concept of equivalent exposures. EV is in fact just a name for the set of shutter/aperture combinations which give an Equivalent Exposure. Not absolute, just relative. Not any one exposure, no ISO, just a name for the numerical set of equivalent shutter/aperture combinations.

Whether close or not, it is the system I learned in school that has worked with remarkable accuracy for 20 years.

If you increase shutter speed one stop, and open aperture one stop, that is still equivalent exposure at any ISO. If you only change one of them, that moves you to the next row. That's what the EV chart shows.

Agreed here. Only meant to point out that this two part relationship can easily be expanded to three parts, and that gives absolute exposure value.

OK, you can pretend to arbitrarily assign an ISO, and then make claims for your new concept regarding exposures, so long as you always explain about your ISO. But ISO is not in the chart.

Arbitrary? yes. 0 is just an arbitrarty starting point commonly used in science and engineering, you're dead on there. New concept? at least twenty years old and coming from a creditable source, and I imagine mine was not the first class to hear it. Here is a couple of charts giving the EV stops as well as the EV numbers in footcandles and lux, which are absolute measures of light.

http://www.fredparker.com/ultexp1.htm

Not my intention to be rude here, not to anyone and not to WayneF, but it is what it is. EV is an absolute measurement of the quantity of light (lux), which makes it highly reliable for walking into a scene, knowing it is EV16 or whatever, and doing half a sec of numbercrunching and hitting manual settings (aperture, shutter speed and ISO) right from the starting gate.

Jim

jimalexander said:

one cannot say that EV15 is the same exposure value so that "we can run ISO from the least value to its highest value, and it remains EV 15, at any ISO ... at any resulting exposure."

Click to expand...

Whether close or not, it is the system I learned in school that has worked with remarkable accuracy for 20 years.

Click to expand...

EV is much older than 20 years, Wikipedia says "The EV concept was developed in an attempt to simplify choosing among combinations of equivalent camera settings, by the German shutter manufacturer Friedrich Deckel (de) in the 1950s".

i.e., EV is about camera settings.

Wikipedia (and others) say the Formal Definition is:

Of course, all of this is without any mention whatsoever of ISO or light value or exposure. Just how it is. EV is about numerical camera setting combinations, independent of ISO or light value.


But yes, sadly, I have to agree that we have greatly corrupted this original meaning since the internet, with all the newbies now throwing in their own comprehension problems with it. Not everyone gets it right, and then they confuse the rest. If we can't make sense of the original concept, then we do seem to imagine it must say ISO 100 somewhere (but it does not mention ISO).

So yes, this original correct definition is becoming unquestionably in the minority now, but here are a few sites that still understand it correctly:

Exposure Value and Exposure Compensation | pixelogist.me "So, you can always know that f2.8 and 1/15 will always be EV7."

Photography Techniques and Equipment discussion: The value of light... Exposure Value defined "In photography, the Exposure Value (EV) is a relationship between the f-stop and the shutter speed independent of ISO and Light Value"

Photography techniques: The EI (exposure index) "It is important to note that the exposure index is not a direct measure of how well your film will be exposed, since it is independent of film speed."

Exposure value - Wikipedia, the free encyclopedia (of course)


I too do prefer to honor the original correct definitions.

I'm sure neither of us is ever going to agree, so let's just leave it there. Nothing is going to change.


I will add this, from the 1700 page "Focal Encyclopedia of Photography", 1969 edition (45 years). Essentially all that was known at that time. The definition has been this way a long time.




Hope it is readable (click it for slightly larger version). It shows exactly the SAME information as Wikipedia.. i.e., there is absolutely no mention of ISO or film speed. It is NOT about light value or absolute exposure.

EV is a name for the equivalent exposure combinations of numerical values of shutter speed and f/stop. Period. Most web sources today are simply wrong, which may be their preference to think they know, but we can't have newbies making up stuff.

WayneF

The sources you cite don't mention ISO, and I feel comfortable assuming your sources are older than mine by the look of them, so I concede you are probably right that was the original meaning and definition of EV. I also know the EV scale is logarithmic and I'm not sure if the ISO stops are truly logarithmic stops or just linear multipliers. The three-part method I use is probably not spot on if it is mincing logs and linear stops... it is probably close enough for practical photography but not accurate enough to be completely true. Thanks for throwing out your sources

I have found the method I was taught invaluable (even if not entirely true to the terms, meanings and math) in that I can go into a room at 9 EV and come to a recipe like 3 stops aperture, 3 stops ISO (800) and 6 stops shutter speed and be ready to shoot, and I can cut shutter speeds in low light by the same number of stops in increasing ISO. Anyway...

Thanks for the lesson.

Jim

jimalexander said:

WayneF

The sources you cite don't mention ISO, and I feel comfortable assuming your sources are older than mine by the look of them, so I concede you are probably right that was the original meaning and definition of EV. I also know the EV scale is logarithmic and I'm not sure if the ISO stops are truly logarithmic stops or just linear multipliers. The three-part method I use is probably not spot on if it is mincing logs and linear stops... it is probably close enough for practical photography but not accurate enough to be completely true. Thanks for throwing out your sources
I have found the method I was taught invaluable (even if not entirely true to the terms, meanings and math) in that I can go into a room at 9 EV and come to a recipe like 3 stops aperture, 3 stops ISO (800) and 6 stops shutter speed and be ready to shoot, and I can cut shutter speeds in low light by the same number of stops in increasing ISO. Anyway...

Thanks for the lesson.

Jim

Click to expand...

We can both be right if we go at it right... at least enough to agree about the obvious facts.

The first line of Wikipedia says about EV:

"In photography, exposure value (EV) is a number that represents a combination of a camera's shutter speed and f-number, such that all combinations that yield the same exposure have the same EV value (for any fixed scene luminance)."

So it is about the numerical combinations. There is no mention of ISO or of light value. Technically, "for ANY fixed scene" means "independent of luminance". Whatever the luminance is, the EV value is about the combination of numbers, as said.

So this means (from the chart): f/16 at 1/125 second is EV 15. ISO and/or proper exposure is NOT a factor. f/16 at 1/125 is EV 15. Period.

We do think of this as being about the correct exposure in bright sun (Sunny 16), except the EV table does not mention the light or the ISO.

If we expose at ISO 100 and get a proper exposure in the sun, then great, but f/16 1/125 second is still EV 15.

If we expose same at ISO 800 and get three stops overexposure, so be it, but f/16 1/125 second is still EV 15, which is not about the light or the proper exposure.

But, if then we know (by some other way) to increase shutter speed 3 stops to 1/1000 second, maybe we get a proper exposure again.
But we have a different combination of numbers now, and now we have to say that f/16 1/1000 second is EV 18 (from the chart. proper exposure or not).

Again, the EV chart did NOT advise us about the sunlight or ISO 100, it only shows shutter/aperture combinations in rows of equivalent exposures... not necessarily proper exposures of anything, not about any ISO, just columns of combinations of numbers that give the SAME exposure (equivalents, good, bad, or indifferent exposure). And concerned with steps in stops (rows of chart). Which was kinda of a big deal back in its day... aperture numbering systems other than f/stops were common until up in the 1920s.

The EV chart, and the concept of it, is about the numerical camera settings, only about shutter speed and fstop.


Now I will switch and argue for your side:


But... later on (after the chart), light meters came into use, and we found light meters could be calibrated in EV.

If the light reads a certain level, we could calibrate the meter and call it EV 15, and then the meter (not the chart, but the meter) told us proper exposure to match that reading. For any ISO, it tells us something. From the chart, if we knew EV 15, then we could derive the proper number combinations matching EV 15. Simply because the meter chose this scheme, to use the EV chart. The chart just tells us combinations for EV 15.

However, it was more useful and straight forward if the meter simply told us the numerical combinations to use, so mostly they do.

Sekonic meters have a special mode where they will read and display EV. They also have an ISO setting that cannot be ignored (it is after all a light meter). And for the current ISO setting, it does give an EV result from the light. And if we change ISO (in the same light), we get a different EV. So the Sekonic mode is NOT independent of ISO, but neither does it show the same information that any EV chart shows (which is independent). Simply not the same concept. This part is about light meters, and the first section above is about EV charts. The meter usage might suggest ISO was a factor of EV (Their way - concerned with ISO and exposure), but the EV chart does not suggest anything of the sort (concerned with equivalent combinations).

You are arguing one way, about meters, and me the other, about charts, but we could simply both agree that both aspects exist.

WayneF said:

You are arguing one way, about meters, and me the other, about charts, but we could simply both agree that both aspects exist.

Click to expand...

I see your point. I don't know if light meters twenty years ago gave "absolute EV" the way my last one did, but someone showed me how to think through the lighting situation in that kind of way way back when and i assumed that was the standard way of doing it. thanks for taking the time to show me this.

Jim