Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
07-28-2015, 11:27 PM   #16
Site Supporter
Sandy Hancock's Avatar

Join Date: Feb 2012
Location: Adelaide Hills, South Australia
Photos: Gallery | Albums
Posts: 5,368
The 50/1.8 will work on a full frame camera, but if you can justify buying that body you will be able to afford other lenses too.

08-15-2015, 08:47 AM   #17
Veteran Member
patarok's Avatar

Join Date: Jul 2013
Posts: 351
QuoteOriginally posted by AntonioD Quote
Thanks, rawr and Canada_Rockies!!! I appreciate the helpful information. For what it is worth, here is what I would like to shoot and print:

I know a lot of the cashiers at the stores that I frequent, and I would like to take their portraits, as well as those of the workers in my dentist and doctor offices. Since these will be in tight spaces, I need a lens that can handle the closeness. As well, I want a good bokeh and very, very shallow depth of field. I want only the eyes and face to be in focus!

As far as prints go, I imagine having mine hung in a gallery space at some point. So, I need to be able to enlarge to gallery size, or larger if I sell a print and someone wants a big enlargement.

It is for these reasons -- shallow DOF and potentially big enlargements -- as well as my subject matter: portraits, for which I think that a FF would be better. Also, if a friend ever asked me to do a wedding, I am told that brides know to ask if your camera is full frame or not, so I want to be prepared for ANYTHING! :-)

P.S. Is a Pentax FF available NOW? I thought that it was not. Please advise! Thanks!
my 2 cents on your questions:

If you want a shallower depth of field, you have to stay with APS-C... If you want to go full frame and you want the same depth of field you have with the DA 50mm 1.8 wide open, you will have to buy at least the FA 50mm 1.4 or the DA*55m 1.4(its weather resistant) ... or you go longer and buy a 85mm lens...(but they - the fast ones - are much more expensive) The "Pentax SMC 50mm 1.2" would also be an option for you but has got no AF...

Keep in mind, that an 85mm is optimal for shots of the whole body of a model...(Fashion shots) and is very good for making objects pop off a background.
(depends on how far you go away... ) But you will see that, a FF camera in fact widens the DoF and the gradients from sharp to blurry are much smoother respectively the DoF will extend. (In comparison with an APS-C DSLR that has an optic with the same focal length mounted and its nodal point is exactly the same length away from the object as the FF) But i really can not make a conclusion for you... Maybe a 100mm 2.4 WR will do right for you. Because basically a 100mm lens has a much shallower depth of field if you come very close to the subject even when your fastest stop is 2.4 or 2.8( it should be app. a little bit less then the half DoF that a 50mm at 1.4 at the same distance will show) but since this lens is a "real" macro lens i can't explain how it will behave if you get really really close to your subject. Because my theoretical experience in macro photography doesn't reach that far as it does with normal photography...



and none of the fast lenses is good in harsh light situations when wide open.. you will have to stop down a 1.4 to at least 1.6 to get good results in very good lit situations.

And if you shoot weddings, do not try to get shallow depth of field.... you can try that in the studio when you do portrait shots of the couple

I can give you another general tip: Watch out for the close-focus ability of the lens you want to buy...

I also like all the very shallow DoF photos because the look so artistic... But remember: Good photos are sharp photos... the Object you want to emphasize in a picture, should be sharp from back to front. (That is the reason so much professionals insist on shooting with full frame cameras ...see my explanation about DoF differences between APS-C and FF...

Have fun...
08-16-2015, 09:12 PM   #18
Pentaxian
mcgregni's Avatar

Join Date: Sep 2012
Location: Surrey, England
Posts: 1,590
Will my K-3 lens work with the anticipated full frame?

I think you may have that round the wrong way, patarok .....the larger the sensor, the more shallow Dof for the same focal length. So a 50mm 1.8 on full frame will have less Dof than the same lens on apps-c .... Perhaps you'd need a 1.4 lens on apps-c to get the same effect ? So our OP would get more out of focus effect on FF.

But the consensus here seems to be that Pentax apps-c equipment currently available is more than up to his task, and of course would involve much less expense than a move to a FF system, of any brand .

I agree entirely with all the good points made above about closeness of focussing and high contrast situations .
08-17-2015, 03:47 AM   #19
Veteran Member
patarok's Avatar

Join Date: Jul 2013
Posts: 351
QuoteOriginally posted by mcgregni Quote
I think you may have that round the wrong way, patarok .....the larger the sensor, the more shallow Dof for the same focal length.



That is a widespread hearsay, that i often read... but i am tired of reading it all the time... so Iet me explain things to you.



Simply: WRONG.... Either you have mistaken something or i got the meaning of the word "shallow" wrong. But maybe your failure has to do with a deceptiveness that is about scale... i dunno.
But please let us hold on to the facts. For example:

If you go and and take a pic of your gf, with a 1.6 stop on 50mm you will get her face sharp but not the face of her brother standing beside and a bit backwards..(measured from the point -- or depth layer if you wish so -- where you focusing at(10-15cm) if you shoot it with an APS-C DSLR...
if you do the same shot with a FULL FRAME DSLR with the same optics at the same stop and at the same distance, her brothers face will also be in focus...(given the fact, that he doesn't stand more than app. 15cm away from the point where you are focusing at.)

So the actual DoF is not smaller on a full frame... it is LARGER!!! Despite what one may be able to read on the internet, I am stating this based on the fact that you call DoF also "Range of Focus" and therefore it refers to the RANGE OF FOCUS in the real world and not on the result.(The picture.)
I really don't believe that all guy who wrote DoF calculators and maybe have some university degree can be THAT wrong... no....

It maybe puzzled because the framing is a whole other thing on FF and so your misunderstanding may have something to do with scale, but pal:
wrong is wrong.
Thats the same as the "What's heavier? A bag filled with 1kg of feathers or a bag filled with 1kg of stones?"-Joke...

You may write a rabulistic answer on this reply, but really believe me: I will not care because i know i am right.
The only thing I can do for you is give you a suggestion: Investigate before you write. For instance: Get a DoF calculator and check it out.

sry, for my bad english. maybe the problem lies burried here but if i aint completely drunk at the moment : shallower should mean smaller...

08-17-2015, 04:12 AM   #20
Pentaxian
redcat's Avatar

Join Date: Jul 2014
Location: Paris
Photos: Gallery
Posts: 1,816
yeah, same lens, same settings there will be smaller range of focus on Crop than on FF it means more bokeh with Crop than FF ^^
Bonus :
Online Depth of Field Calculator
08-17-2015, 04:20 AM   #21
Pentaxian




Join Date: Apr 2007
Location: Sweden
Posts: 1,904
QuoteOriginally posted by AntonioD Quote
Since these will be in tight spaces, I need a lens that can handle the closeness.
I guess lack of space is the biggest problem here, some distance and a longer 2.8 lens would give you really thin dof. I have a Tamron 70-200 2.8 and a K5, and with that combo really thin dof can be achieved. But one needs some distance to the object.
08-17-2015, 05:42 AM   #22
Pentaxian
mcgregni's Avatar

Join Date: Sep 2012
Location: Surrey, England
Posts: 1,590
I'm always happy to be wrong if it provokes more discussion and more information. Certainly it has here, so that's good. I thought the consensus here had been that a move to FF would give our OP less DOF all else being equal .... That's not so apparently. I clearly need to read up some more 😊
08-17-2015, 06:44 AM - 1 Like   #23
Pentaxian
redcat's Avatar

Join Date: Jul 2014
Location: Paris
Photos: Gallery
Posts: 1,816
QuoteOriginally posted by mcgregni Quote
My Guide to The Pentax Digital Camera Flash Lighting System : Comprehensive Pentax Flash Guide - Articles and Tips | PentaxForums.com
your Pentax flash guide is amazing ^__^

08-17-2015, 06:57 AM   #24
Pentaxian
mcgregni's Avatar

Join Date: Sep 2012
Location: Surrey, England
Posts: 1,590
Thanks 😊 I hope you find it interesting and informative. I was going to do one on depth of field and sensor formats, but I might put that on hold for now 😃
08-17-2015, 07:31 AM   #25
Pentaxian




Join Date: Apr 2007
Location: Sweden
Posts: 1,904
QuoteOriginally posted by redcat Quote
yeah, same lens, same settings there will be smaller range of focus on Crop than on FF it means more bokeh with Crop than FF ^^
Bonus :
Online Depth of Field Calculator
But the thing is that with the same lens on FF you will move closer to the subject as the lens "appears" to be wider compared to when it is used with a cropped sensor. And when you move closer the dof will change. That is why you will get a shallower dof with ff. You either move closer or you use a longer lens.
08-17-2015, 07:47 AM   #26
Veteran Member
patarok's Avatar

Join Date: Jul 2013
Posts: 351
FTF I also want to thank you for that guide mcgregni...



AND:
(I wish i could, but i can't leave this comment untouched...(call me childish if you want to. )

QuoteOriginally posted by redcat Quote
yeah, same lens, same settings there will be smaller range of focus on Crop than on FF it means more bokeh with Crop than FF ^^
-> more bokeh on Crop is also wrong. because the DoF is just a little bit wider (and just runs out more smoothly) and where there is significant bokeh on APS-C there will also be bokeh on FF. And there will be more to see of it on a picture made with a FF camera, because the frame around the object that is pictured sharp(and is actually reproduced at the same scale on the sensor surface of the FF-sensor as it would be on the APS-C sensor. -RUB-) is bigger because the sensor surface is bigger.

(I just don't like secrets...and i know that may be the reason, why I don't win any popularity contests)
08-17-2015, 09:35 AM   #27
Veteran Member




Join Date: May 2014
Location: Maryland
Photos: Gallery
Posts: 760
QuoteOriginally posted by AntonioD Quote

As far as prints go, I imagine having mine hung in a gallery space at some point. So, I need to be able to enlarge to gallery size, or larger if I sell a print and someone wants a big enlargement.
I just came across the thread while searching for lens. As for as gallery size, K-3 is more than sufficient. Not sure what size you want, but I have had a few entries in shows in galleries and it's fine. When you go very large, your resolution can go down with printing, because of the viewing distance. Billboards for example are printed at a resolution of 12-15 dpi because of the viewing distance. It depends what you want to take photos of and how you want people to view it (do you want them to get up close and look at detail or just look at the overall image) but K-3 is fine. I believe I also made prints with my 16mp camera but can't verify that without going through my prints right now.

Sorry if this is repeated, I just skimmed over the rest of the posts.
08-17-2015, 11:17 AM   #28
Pentaxian
mcgregni's Avatar

Join Date: Sep 2012
Location: Surrey, England
Posts: 1,590
QuoteOriginally posted by patarok Quote
FTF I also want to thank you for that guide mcgregni...



)

Thanks .... Let me know how you find it. I intend to make revisions for corrections and new information over time .....
08-24-2015, 12:42 PM   #29
Loyal Site Supporter
UncleVanya's Avatar

Join Date: Jul 2014
Photos: Gallery | Albums
Posts: 9,716
QuoteOriginally posted by patarok Quote



That is a widespread hearsay, that i often read... but i am tired of reading it all the time... so Iet me explain things to you.



Simply: WRONG.... Either you have mistaken something or i got the meaning of the word "shallow" wrong. But maybe your failure has to do with a deceptiveness that is about scale... i dunno.
But please let us hold on to the facts. For example:

If you go and and take a pic of your gf, with a 1.6 stop on 50mm you will get her face sharp but not the face of her brother standing beside and a bit backwards..(measured from the point -- or depth layer if you wish so -- where you focusing at(10-15cm) if you shoot it with an APS-C DSLR...
if you do the same shot with a FULL FRAME DSLR with the same optics at the same stop and at the same distance, her brothers face will also be in focus...(given the fact, that he doesn't stand more than app. 15cm away from the point where you are focusing at.)

So the actual DoF is not smaller on a full frame... it is LARGER!!! Despite what one may be able to read on the internet, I am stating this based on the fact that you call DoF also "Range of Focus" and therefore it refers to the RANGE OF FOCUS in the real world and not on the result.(The picture.)
I really don't believe that all guy who wrote DoF calculators and maybe have some university degree can be THAT wrong... no....

It maybe puzzled because the framing is a whole other thing on FF and so your misunderstanding may have something to do with scale, but pal:
wrong is wrong.
Thats the same as the "What's heavier? A bag filled with 1kg of feathers or a bag filled with 1kg of stones?"-Joke...

You may write a rabulistic answer on this reply, but really believe me: I will not care because i know i am right.
The only thing I can do for you is give you a suggestion: Investigate before you write. For instance: Get a DoF calculator and check it out.

sry, for my bad english. maybe the problem lies burried here but if i aint completely drunk at the moment : shallower should mean smaller...
So I think the problem is that we are mixing theoretical answers with practical answers.

Practical impact of FF is shallower depth of field for the types of shots we shoot. Why? Because you use a longer lens at the same distance as you would use a shorter lens. If I shoot the portrait headshot with a 50mm on APSC I will shot that same shot with a 75mm if I want to stand at the same distance from the subject (which I typically will want to do). Taking this into account and plugging in a 50mm 1.7 at 5' I get 0.2' DOF; but with the 75mm at 5' I get .13' DOF. Pragmatically it results in lower depth of field. Furthermore if I simply walk closer (to 3.35 feet) with the 50mm to get the same subject framing. In the process I also end up with less DOF.

Don't just take my word. Use the Dimensional Field of View calculator on this site and either the originally supplied DOF calc or the one on that page. It is certain that if you look at very large format cameras and very small format cameras the practical effect of DOF is that smaller sensors give higher DOF for a given subject framing. The reasons are complicated but the result is not.

Easy to see in practical action... shoot a portrait with a P&S or Phone and do the same with the camera of your choice with a larger sensor. Use the same f/stop. Framed the same - which appears to have more DOF?

---------- Post added 08-24-15 at 03:49 PM ----------

Oh I forgot to tie this back to the original question.

Yes APSC and FF both can provide nice short distance portrait options. The 50mm f/1.8 is not a bad choice. There is no one here who can tell you if it will work in full frame mode - test shots seem to show it could - until the FF is released nobody knows what it will support other than crop mode for DA lenses and FF for D FA lenses. In the meantime it is certain that the DA 50 f/1.8 works nicely on a K3 as a short portrait lens. I personally like a DA 40 Limited f/2.8 for that kind of shot but my working distances may be shorter than your are saying. Play with a zoom lens on the K3 and decide what focal length works for your purpose.

Later if you want to do this with FF - you are likely to want a different lens because of the increase in the width of the field of view lenses give for the same focal length. SO while you could use the 50 - you may end up closer to the subject than you want to be - at least on FF when not shooting in cropped mode. You could buy a longer lens now - but it would negatively impact your stated use - close portraits with shallow DOF. The longer lens might push you too far from your subject until you switched to FF. Point being - buy a K3 and a 50 f/1.8 now; worry about later, later.

Last edited by UncleVanya; 08-24-2015 at 12:52 PM.
08-24-2015, 02:53 PM   #30
Veteran Member
patarok's Avatar

Join Date: Jul 2013
Posts: 351
Comparing apples with oranges here... despite there are worlds between the optical construction of P&S and DSLR lenses(not to say how shutter&aperture work differntly..)...have a drink. calm down. Now we know you are here... i was writing this with AntonioDs issue in mind. READ:

Guy wants to buy DA 50mm 1.8 and it seems he's expecting it to work on FF. It will. He thinks he will get shallower DoF with FF. If he mounts that lens and works as he is used to that is simply wrong. One can always go closer to a subject to shrink DoF. But however...Every lens has a closest focusing distance given.

AntonioD wants the shallowest DoF he can get with the DA 50mm 1.8 he considers to buy. !!!!!

QuoteOriginally posted by AntonioD Quote
I want a good bokeh and very, very shallow depth of field. I want only the eyes and face to be in focus!

The DA 50mm 1.8 has a CFD of 45cm... he will not be able to focus if he gets closer to the point where he wants to focus on than 45cm. right? fact.
I want to annotate that, antonios issue was about, how to get the shallowest DoF possible. it was not about framing. So he will get as close as possible with what he has. A DA 50mm 1.8....(Hey may for some reason stop it down to 2.0)


Pentax DA 50mm 1.8 at an aperture stop of 2.0 (45cm distance. -> closest distance at which the lens still will be able to focus)

APS-C DSLR: app. 0.58cm DoF
FF DSLR: app. 0.84cm DoF

Simple as that. theoretical and practical.

close focus, shallowest DoF... AND AGAIN: IF you do the same shot with a FF camera, there will be exactly 0.26cm less DoF than on APS-C theoretical and practical. AND there will be more background around the face you focused on. The lens will not magnify less or more just because you put it on a FF. So there is no reason to go away. From the subject... This was just to give an ANSWER to AntonioDs question.

And you may ask:
Attached Images
 
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
24x36mm, 50mm, canon, depth, distance, dof, ff, field, frame, full-frame, k-3, k-3 lens, k3, lens, lenses, pentax, shot, subject
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
The Full Frame: What will make you buy it? mikeodial Pentax Full Frame 130 07-27-2016 05:53 PM
Full Frame vs Micro 4/3 Revisited with Pro Olympus Lens interested_observer Non-Pentax Cameras: Canon, Nikon, etc. 6 05-18-2015 10:34 AM
Is a K-3 with a full frame sensor enough for you? jake14mw Pentax Full Frame 58 03-28-2015 11:39 AM
If Pentax went Full-Frame would my APC Lenses work? mdshooting Pentax Full Frame 15 12-06-2014 09:54 PM
how do i know if a lens will work with my k-x? jupzchris Troubleshooting and Beginner Help 17 08-01-2010 09:52 AM



All times are GMT -7. The time now is 09:14 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top