[bertwert]

Oh dear. I thought we had moved on and were done with this equivalence stuff...

[Zygonyx]

What a eck didn't they change mount to make APS-C to FF lenses not possible to fix

[normhead]

Just want to clarify on the part being able to expose at f1.4 @ APS-C,it can be misunderstood as meaning you will get the light of the full 1.4 aperture on APS-C as you will not. Like you correctly stated it will be more like an aperture of 2.0 as you only get a portion of the light on the smaller APS-C sensor.

The only way to get nearly the same amount of light from a FF lens on an APS-C body would be a metabones speed booster afaik.

Not quite.

ƒ1.4 is the only setting for which that's true.

For example when I take my K-1 and K-3 out with the 70 on the K-3 and the 100 on the K-1 if I compensate for DoF and shoot ƒ5.6 on the K3 and ƒ8 on the K-1, not only do I get the same amount of DoF, the same amount of light is used on both sensors. Twice the intensity of light on half the size sensor.

This has always been a slight of hand, designed to make it sound like every FF sensor image uses twice as much light as an APS_c image, where, for the same DOF, they use exactly the same amount of light.

Only at ƒ1.4 where you'd have to go to ƒ1 to match the DoF, does this become a problem. On 99% of images, you can use the same light if you want to. It's your choice.

I have 1244 keepers in my current library. One was taken at 1.4, and it wasn't taken this year. This may be big deal for some, but I'm not sure who.
Someone step up and say "25% of my images are taken at ƒ1.4". We know there's someone out there somewhere. SO for me .1% of my images taken on my K-1 could not have been taken with my K-3. The other 99.9% would have used the same light taken on my K-3. And yes, I do shoot the K-1 with a one stop smaller aperture than I do my K-3. K-3, standard is 5.6. K-1 standard is ƒ8.

[bertwert]

For example when I take my K-1 and K-3 out with the 70 on the K-3 and the 100 on the K-1 if I compensate for DoF and shoot ƒ5.6 on the K3 and ƒ8 on the K-1, not only do I get the same amount of DoF, the same amount of light is used on both sensors. Twice the intensity of light on half the size sensor.

Uh.... assuming the same scene and light, the K-1 image would be a stop underexposed... unless you slowed the shutter speed by a stop as well...

[normhead]

Uh.... assuming the same scene and light, the K-1 image would be a stop underexposed... unless you slowed the shutter speed by a stop as well...

Read more at: https://www.pentaxforums.com/forums/16-pentax-news-rumors/408001-dfa-85mm-f-...#ixzz6O3bhLr6s

K-1. ƒ8, 1/100s, 200 ISO
K-3 ƒ5.6 1/100s 100 ISO

F8 1/100s 100 ISO on the FF would be a not functional setting because the K-3 would be over-exposed, exposure is not affected by sensor size . ƒ8 is ƒ8 for exposure. But that's not a practical issue, because the difference between 100 and 200 ISO on both cameras is negligible. But, ƒ1.4, 100 ISO is the FF advantage. At any other ƒ-stop and aperture, APS-c can use the same amount of light if desired. It's not a universal truth as implied.

But honestly why would you care? If you get the image you want, who cares how much light you use? You get one stop improvement in noise. But if you get the image you want, the amount of light used is moot.

We did this experiment once with the K-5 and my K-1. The exposures were different but the image were indistinguishable. This is debate material. Not real world photography material in all but the most extreme circumstances..

[Dartmoor Dave]

Hmm, I though to myself. Why is that thread about the 85mm/1.4 so busy? There must be something really interesting about that lens that's worth reading about, even though it's not one I'd find any use for myself. Maybe I should have a look at the thread?

And now I've looked, and I'll never unsee the horror of it. The equivalence zombies HAVE RISEN FROM THE DEAD!

Noooooooooooooooooooooooooooooooooooooo...............................!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[carlb]

Me..........I just stick a lens on my camera and take a picture. This thread should be celebrating the launch of, what I'm sure will become, one of the classic Pentax lenses and it's turned into a p*****g contest over minute details that's run to god knows how many pages now.

[Dartmoor Dave]

And here's another thing. Portraiture is all about capturing and revealing the character of the person in the photo, and usually the best way to do that is by showing them in some sort of a context that's reasonably in focus and says something meaningful about them.

99% of the photos on the internet where somebody has just grabbed his fastest medium telephoto and set the aperture wide open to get a blurry background have got nothing to do with portraiture at all. They are just some onanistic gear collector wanting to show everyone what a flashy lens he can afford.

[normhead]

Me..........I just stick a lens on my camera and take a picture. This thread should be celebrating the launch of, what I'm sure will become, one of the classic Pentax lenses and it's turned into a p*****g contest over minute details that's run to god knows how many pages now.

You're a smart man. It always comes down to FF guys saying "my camera is better than yours, it uses more light and that's better., neener, neener."

---------- Post added 05-31-20 at 05:41 PM ----------

They are just some onanistic gear collector wanting to show everyone what a flashy lens he can afford.

Sad but true.

It took me a couple of years shooting APS-c to discover I wasn't shooting an FF camera. But it's a big deal for some. I even like my 1 inch and 1.23 sensor images. They may use a fraction the light but they look the same on my 4k TV, and the prints give off the same amount of light as the same size print on my wall even I they were taken with 10 times the light. It's an import parameter that makes very little difference to the output. One is not twice as bright on my computer monitor.

There has never been so much time wasted on a debate that has so little value, since clerics argued about how many angels could fit on the head of pin.

[robbiec]

Harsh

My primary reason for getting hold of this new 85 is this young lady, my 4yo daughter Hazel. I've other reasons too, I like the Pentax system, I am liking the transitions from focus to out of focus that I've seen so far, I like the fact that it will be built to the same quality as its little brother, I like the philosophy of what the engineers set out to do. The whole crop vs FF is null and void to me, I jump between both as I see fit or whichever camera is closest to me at the time.

I suppose what I'm trying to say here is that I reject the notion that I'm a gear obsessed, wealthy collector. I rarely publish photos of my daughter but I have thousands, and I won't bat an eyelid at the price, weight if it gets me a single wow shot of her over the coming months, because touch wood if in 20 years time I'm still around, I'll be able to look back, and see through imagery my baby girl growing up.

We all have our reasons for photography, some like me are in it as a hobby, some make it their professional role in life, some like the technical aspect, some the artistry.

So perhaps we can shut out the naysayers from other camps, naysayers that don't see the value or engineering nous needed to create this optic and celebrate its release, its availability, and the sheer hard work & talent to develop this lens and concentrate on what it might be able to do, which is capture that moment in time before it is lost except in our memories with its own unique flavour.

It us all about the images after all and for me, a lot will be of a doting father taking shots of his daughter. Price of that is €2000, value to me is priceless.

[pschlute]

Oh...did someone mention "equivalence" ? (grabs beer and packet of crisps)

.....actually I do have one question that no-one has managed to answer yet about "equivalence".........

On my Seconic incident light meter, I cannot find the menu item where I have to dial in the format that I am using....I am sure it must be there somewhere

[bedisaab]

Harsh

My primary reason for getting hold of this new 85 is this young lady, my 4yo daughter Hazel. I've other reasons too, I like the Pentax system, I am liking the transitions from focus to out of focus that I've seen so far, I like the fact that it will be built to the same quality as its little brother, I like the philosophy of what the engineers set out to do. The whole crop vs FF is null and void to me, I jump between both as I see fit or whichever camera is closest to me at the time.

Eg, K-3 + K55/1.8
https://www.flickr.com/gp/theconniseur/u5920B

Or K-1 + 77 Limited
https://www.flickr.com/gp/theconniseur/G7Wbc1

I suppose what I'm trying to say here is that I reject the notion that I'm a gear obsessed, wealthy collector. I rarely publish photos of my daughter but I have thousands, and I won't bat an eyelid at the price, weight if it gets me a single wow shot of Hazel over the coming months, because touch wood if in 20 years time I'm still around, I'll be able to look back, and see through imagery my baby girl growing up.

We all have our reasons for photography, some like me are in it as a hobby, some make it their professional role in life, some like the technical aspect, some the artistry.

So perhaps we can shut out the naysayers from other camps, naysayers that don't see the value or engineering nous needed to create this optic and celebrate its release, its availability, and the sheer hard work & talent to develop this lens and concentrate on what it might be able to do, which is capture that moment in time before it is lost except in our memories with its own unique flavour.

It us all about the images after all and for me, a lot will be of a doting father taking shots of his daughter. Price of that is €2000, value to me is priceless.

You spoke my words here. As I posted before I’m buying this lens for my son & going to keep taking his portraits till he graduates from the college & he’s 21 months old.

[Class A]

On my Seconic incident light meter, I cannot find the menu item where I have to dial in the format that I am using....

A light meter does not need to know the format because "exposure" is defined in a format-independent manner; it refers to light intensity, not total amount of light.

For image quality, however, total amount of light is relevant, not exposure. This is why large format cameras were used for serious work and what is referred to as FF today was ridiculed as an amateur format.

N.B., a good DOF calculator will require you to select the format. Why is that if "f/1.4 is f/1.4 on all formats"?

[Wheatfield]

You spoke my words here. As I posted before I’m buying this lens for my son & going to keep taking his portraits till he graduates from the college & he’s 21 months old.

I'm buying it because I like shiny stuff.

[normhead]

You spoke my words here. As I posted before I’m buying this lens for my son & going to keep taking his portraits till he graduates from the college & he’s 21 months old.

It looks to be a great lens, and if you look at the cost over the life of the lens, it's not that much a month, or even a year.