[Arjay Bee]

DA70 does well.

[giselag]

Thanks



It's full-frame. You could use it on K-3, and keep it if for K-1 if you later decide to upgrade the camera body.

I am assuming that the 85mm becomes more like a 127 mm on a K3 crop sensor. What about the f1.4? Does it affect that?

---------- Post added 05-01-17 at 11:06 AM ----------

If the 50mm isn't doing it for you, it sounds like you just need a longer lens. The FA 77mm would be a great contender, IMO.

The FA 77mm would essentially be 117 mm on a k3. Do you use it on a full frame camera or on a crop sensor camera? If you use this lens on
a crop sensor camera, how else does it affect the shot?

[Adam]

I am assuming that the 85mm becomes more like a 127 mm on a K3 crop sensor. What about the f1.4? Does it affect that?

---------- Post added 05-01-17 at 11:06 AM ----------




The FA 77mm would essentially be 117 mm on a k3. Do you use it on a full frame camera or on a crop sensor camera? If you use this lens on
a crop sensor camera, how else does it affect the shot?

The focal length never changes, it's just a tighter field of view. Still fine for portraits on either format IMO.

[giselag]

The focal length never changes, it's just a tighter field of view. Still fine for portraits on either format IMO.

Ok.. Just wondering because I was watching a video by a photographer, Tony Northrup, who said that a full frame lens on a crop sensor camera changes an f1.4 to about a f4 on a crop sensor. I've never heard anyone say that before. I know that the 77 mm has to be multiplied by 1.5 on a crop sensor and creates a tighter field of view but I didn't think if affect anything else.


Also, Will autofocus work on this lens with my k3 or would it be totally manual focus?


Trying to make a wise decision for my next lens purchase while I wait to be able to afford to go full frame.


Thanks for all your help and advice.

[Adam]

Ok.. Just wondering because I was watching a video by a photographer, Tony Northrup, who said that a full frame lens on a crop sensor camera changes an f1.4 to about a f4 on a crop sensor. I've never heard anyone say that before. I know that the 77 mm has to be multiplied by 1.5 on a crop sensor and creates a tighter field of view but I didn't think if affect anything else.


Also, Will autofocus work on this lens with my k3 or would it be totally manual focus?


Trying to make a wise decision for my next lens purchase while I wait to be able to afford to go full frame.


Thanks for all your help and advice.

Nope, the aperture or light transmission never changes.

FA lenses are full autofocus / auto exposure.

[Sandy Hancock]

Ok.. Just wondering because I was watching a video by a photographer, Tony Northrup, who said that a full frame lens on a crop sensor camera changes an f1.4 to about a f4 on a crop sensor.

Well there's your problem. Don't believe anything Tony Northrup says

Equivalence is a rabbit hole you don't want to go down, but the statement above is complete nonsense (like two stops out). Because the angle of view changes when you change formats, you have to change the distance from the camera to subject to get the same framing. Because the distance changes, so does the depth of field at any given aperture.

So, if you shoot a head shot on full frame with a 85/1.4 wide open, and a head shot with the same lens at the same settings on a crop camera, you will have to move further away from subject, so the depth of field will be greater. You will end up with an image roughly equivalent to what you'd get from a 115mm lens at f/2.0 on a full frame camera taken from the same spot.

But exposure values do not change. The best thing to do until you understand it fully is to forget about equivalence altogether. A fast mid telephoto with give you fantastic bokeh control for portraits on full frame or crop.

[giselag]

Nope, the aperture or light transmission never changes.

FA lenses are full autofocus / auto exposure.

Thank you so much for all the info.

---------- Post added 05-02-17 at 01:42 PM ----------

Well there's your problem. Don't believe anything Tony Northrup says

Equivalence is a rabbit hole you don't want to go down, but the statement above is complete nonsense (like two stops out). Because the angle of view changes when you change formats, you have to change the distance from the camera to subject to get the same framing. Because the distance changes, so does the depth of field at any given aperture.

So, if you shoot a head shot on full frame with a 85/1.4 wide open, and a head shot with the same lens at the same settings on a crop camera, you will have to move further away from subject, so the depth of field will be greater. You will end up with an image roughly equivalent to what you'd get from a 115mm lens at f/2.0 on a full frame camera taken from the same spot.

But exposure values do not change. The best thing to do until you understand it fully is to forget about equivalence altogether. A fast mid telephoto with give you fantastic bokeh control for portraits on full frame or crop.

Thank you for the information.

[JimJohnson]

Going from film to APS-C digital I used to let myself get hung up on the field of view issue. Mentally I used to drive myself nuts translating everyday things back & forth between metric and American measurement systems. In both cases, I just got used to the relationship of numbers within one measurement system and didn't worry about the other measurement system.

When I shot film, I just worried about good composition. And in my own wet lab, I cropped stuff all the time. Exposure and bokeh didn't change just because I only enlarged part of the frame. Well the exact same thing is happening here. The registration distance between the rear element of the lens and the light sensitive surface is exactly the same in my Super Program as in my K-3. So just like in my wet lab, the only difference is how much of the frame is being used. With my K-3, I'm just worrying about good composition.

[giselag]

Going from film to APS-C digital I used to let myself get hung up on the field of view issue. Mentally I used to drive myself nuts translating everyday things back & forth between metric and American measurement systems. In both cases, I just got used to the relationship of numbers within one measurement system and didn't worry about the other measurement system.

When I shot film, I just worried about good composition. And in my own wet lab, I cropped stuff all the time. Exposure and bokeh didn't change just because I only enlarged part of the frame. Well the exact same thing is happening here. The registration distance between the rear element of the lens and the light sensitive surface is exactly the same in my Super Program as in my K-3. So just like in my wet lab, the only difference is how much of the frame is being used. With my K-3, I'm just worrying about good composition.

Thank you

[adjutant]

Well there's your problem. Don't believe anything Tony Northrup says

Equivalence is a rabbit hole you don't want to go down, but the statement above is complete nonsense (like two stops out). Because the angle of view changes when you change formats, you have to change the distance from the camera to subject to get the same framing. Because the distance changes, so does the depth of field at any given aperture.

So, if you shoot a head shot on full frame with a 85/1.4 wide open, and a head shot with the same lens at the same settings on a crop camera, you will have to move further away from subject, so the depth of field will be greater. You will end up with an image roughly equivalent to what you'd get from a 115mm lens at f/2.0 on a full frame camera taken from the same spot.

But exposure values do not change. The best thing to do until you understand it fully is to forget about equivalence altogether. A fast mid telephoto with give you fantastic bokeh control for portraits on full frame or crop.

Couldn't have said it better myself. This sums it all up if you're wondering why people apply crop factor to the aperture, and how it only refers to equivalent depth of field, not light gathering ability.

[Rupert]

I haven read very post here....maybe someone has mentioned it? The Bokeh Thread is a great place to view different bokeh from different lenses.
The Bokeh Club - PentaxForums.com

I see all types of bokeh there from creamy smooth to excitedly busy.

My Bigma delivers some unusual bokeh quite often. Some pleasing to my eyes, but I never know just what I might get. Replicating depends on many factors other than the lens itself....as has been noted.

This one surprised me.....didn't see it coming!


Regards! & Good luck on finding what will thrill you!

[MrTiburon]

Well I know it's old thread - but shuffling through the forum I've just spotted it. I have really old Makinon mc ZOOM f=28-80mm 1:3.5. It's probably oldest lens I have - calling it Grandpa Lens. Few dents on the hood, tons of dust and something rattling when you give it a shake - but it can give you nice bokeh. I'd really recommend this one if you can get it cheap. I'd say this lens is indestructible...