Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-20-2018, 06:49 PM   #1
Site Supporter
Site Supporter




Join Date: Feb 2018
Location: NoVA
Posts: 600
Grand Lens Test 1: 645 FA 400/5.6 ED(IF)

Let's start here. Remember, I applied no sharpening, and only applied whatever corrections DXO Photolab has built into its database, which is nothing for this lens.

Here's the scene, shot with the 35 in better light (lighting was very flat for my test photos). The focus point is the lamp. Remember, the 1:1 crops are part of an image that would be 7 feet wide printed at the 100 pixels/inch of most screens.



400/5.6 at 5.6 full scene:


The bokeh of this lens isn't spectacular, in my view--the out of focus areas are busy wtih evidence of bright-line rendering. But that's not really what this lens is for--I worry about that on a shorter lens.

Here's the center at f/5.6:


And here's the center at f/11 (optimal for this lens):


I'm happy to use this lens wide open.

But how does it do with a 1.4 extender?

400, plus 1.4 extender, full image:


Bokeh is no better, of course.

Here is the center at 5.6:


And at f/11:


It's a little better at f/11, but I'm still happy to use this at f/5.6.

This is a great lens, even with the 1.4 converter.

Rick "pondering which one to do next" Denney

05-21-2018, 12:59 AM   #2
Senior Member




Join Date: Mar 2016
Location: La Vienne (86), France
Posts: 223
Encouraging results Rick and thanks for publishing your findings. I picked up a copy of this lens a few days ago and have yet to use it in anger.

(small point about the apertures used.....you have the converter assisted shots at "f/5.6" and "f/11" but I'm guessing that these are f/8 and f/16 in reality).

Bob
05-21-2018, 09:05 AM   #3
Site Supporter
Site Supporter




Join Date: Feb 2018
Location: NoVA
Posts: 600
Original Poster
QuoteOriginally posted by Bob L Quote
Encouraging results Rick and thanks for publishing your findings. I picked up a copy of this lens a few days ago and have yet to use it in anger.

(small point about the apertures used.....you have the converter assisted shots at "f/5.6" and "f/11" but I'm guessing that these are f/8 and f/16 in reality).

Bob


I’m showing the set aperture, not the effective aperture.

Rick “the EXIF is inconsistent on the matter” Denney
05-21-2018, 10:12 AM   #4
Senior Member




Join Date: Mar 2016
Location: La Vienne (86), France
Posts: 223
QuoteOriginally posted by rdenney Quote
I’m showing the set aperture, not the effective aperture.
OK, I'm aligned.

05-23-2018, 05:02 PM   #5
Site Supporter
Site Supporter




Join Date: Nov 2011
Location: pontiac mi.
Posts: 392
QuoteOriginally posted by Bob L Quote
OK, I'm aligned.


Again, try it with the 2x, I get good results.
06-05-2018, 11:54 PM   #6
Site Supporter
Site Supporter




Join Date: Nov 2014
Posts: 335
QuoteOriginally posted by rdenney Quote
Let's start here. Remember, I applied no sharpening, and only applied whatever corrections DXO Photolab has built into its database, which is nothing for this lens.

Here's the scene, shot with the 35 in better light (lighting was very flat for my test photos). The focus point is the lamp. Remember, the 1:1 crops are part of an image that would be 7 feet wide printed at the 100 pixels/inch of most screens.



400/5.6 at 5.6 full scene:


The bokeh of this lens isn't spectacular, in my view--the out of focus areas are busy wtih evidence of bright-line rendering. But that's not really what this lens is for--I worry about that on a shorter lens.

Here's the center at f/5.6:


And here's the center at f/11 (optimal for this lens):


I'm happy to use this lens wide open.

But how does it do with a 1.4 extender?

400, plus 1.4 extender, full image:


Bokeh is no better, of course.

Here is the center at 5.6:


And at f/11:


It's a little better at f/11, but I'm still happy to use this at f/5.6.

This is a great lens, even with the 1.4 converter.

Rick "pondering which one to do next" Denney
Hi Rick - after seeing this, and our other discussion today about the 2x converter , I'm tempted to go in this direction rather then either of the 300mm options.....the 400mm would be a similar fov to a 320mm full-frame,correct? Thks, Ian
06-06-2018, 02:42 AM   #7
Senior Member




Join Date: Dec 2015
Location: Paris area
Posts: 144
QuoteOriginally posted by BostonUKshooter Quote
Hi Rick - after seeing this, and our other discussion today about the 2x converter , I'm tempted to go in this direction rather then either of the 300mm options.....the 400mm would be a similar fov to a 320mm full-frame,correct? Thks, Ian

Yes, to have an equivalent of 645Z FOV in 24x36 format, you remove 20% of the 645 focal length. All this is an approximation, because comparing 2:3 (24x36) format and 4:3 (645) format is not that obvious.
06-06-2018, 06:11 AM   #8
Site Supporter
Site Supporter




Join Date: Feb 2018
Location: NoVA
Posts: 600
Original Poster
QuoteOriginally posted by BostonUKshooter Quote
Hi Rick - after seeing this, and our other discussion today about the 2x converter , I'm tempted to go in this direction rather then either of the 300mm options.....the 400mm would be a similar fov to a 320mm full-frame,correct? Thks, Ian
Look at my review of the 1.4x converter. I found that even though the 300/4 A* is better at f/11 than the 400/5.6 FA, it's not quite as good when put in front of the A 1.4x converter. I would use the converter in situations where I needed to optimize for 300 but also have a 400 capability (300*1.4=420) without having to crop, and particularly when I'm trying to lighten the load. But if I need to optimize at 400 and still have a 300 capability, then I will take the 400, and then maybe the 200 plus the converter (the 200 is much smaller and lighter than the 300, at least the A* 300).

400 is 400 is 400. It will project that distant object onto the sensor exactly the same size as a 400 on a 24x36 camera. The difference is that the 645 will see more of the scene around the edges. Also, different sensor densities will present different enlargement possibilities (assuming the lenses are good enough). For example, my wife might use a 400 on her D500 (APS-C), and I might use this lens on my 645z. If we are only interested in the face of the squirrel we are both photographing, and assuming that we can both see all of the face we want to, her camera will have more pixels in the face than mine will, because the pixel density is (a little) higher on the D500 sensor. If we both enlarge to make a 300 pixel/inch print, her squirrel face will be bigger than mine, but her print will be 12x18", and mine will be 20x28" (nominally). With her older D300, which has the same sensor size as the D500 but fewer pixels, the biggest 300ppi print she could make would be 9.5 by 14.5", and the squirrel's face would be exactly the same size, because both have the same pixel density. So, she'd have a squirrel face, say, 6" tall on a 9x14 print, and I'd have a squirrel face 6" tall on a 20x28 print. So, it's really a complicated comparison when we change formats on real cameras that have different sensors with different pixel densities.

And then the different shape of the format also has implications. If you are normally interested in the long dimensions (such as those who do panoramics), 24x36 will capture more of the scene compared to 33x44 than if you are interested mostly in the narrow dimension. If you normally frame to standard photographic print sizes (8x10, 11x14, 16x20, 20x28, etc.), you'll be more interested in the narrow dimension. If you only show pictures on the internet or on a 16x9 monitor, you may not care or you may be more interested in the long dimension.

Focal length controls the magnification in the camera, while the format (sensor size, not density) controls how much of the scene will be recorded. Pixel density, sensor noise, and lens quality determine how much the image can be enlarged (i.e., magnification outside the camera).

The common method of comparison is to look at the length of the lens as a ratio to the diameter of the format. The diameter of 24x36 is 43mm, and the diameter of 33x44 is 55mm. 55/43=1.28. So, on a 645z, a 400 is 7.3 times the format diameter, and on a 24x36 camera, 43 times 7.3 is 314. But there's far more to the comparison than that.

Rick "answering a much larger question than the one you asked, but having his own preferred way of explaining it" Denney

06-06-2018, 08:40 AM   #9
Site Supporter
Site Supporter




Join Date: Nov 2014
Posts: 335
QuoteOriginally posted by rdenney Quote
Look at my review of the 1.4x converter. I found that even though the 300/4 A* is better at f/11 than the 400/5.6 FA, it's not quite as good when put in front of the A 1.4x converter. I would use the converter in situations where I needed to optimize for 300 but also have a 400 capability (300*1.4=420) without having to crop, and particularly when I'm trying to lighten the load. But if I need to optimize at 400 and still have a 300 capability, then I will take the 400, and then maybe the 200 plus the converter (the 200 is much smaller and lighter than the 300, at least the A* 300).

400 is 400 is 400. It will project that distant object onto the sensor exactly the same size as a 400 on a 24x36 camera. The difference is that the 645 will see more of the scene around the edges. Also, different sensor densities will present different enlargement possibilities (assuming the lenses are good enough). For example, my wife might use a 400 on her D500 (APS-C), and I might use this lens on my 645z. If we are only interested in the face of the squirrel we are both photographing, and assuming that we can both see all of the face we want to, her camera will have more pixels in the face than mine will, because the pixel density is (a little) higher on the D500 sensor. If we both enlarge to make a 300 pixel/inch print, her squirrel face will be bigger than mine, but her print will be 12x18", and mine will be 20x28" (nominally). With her older D300, which has the same sensor size as the D500 but fewer pixels, the biggest 300ppi print she could make would be 9.5 by 14.5", and the squirrel's face would be exactly the same size, because both have the same pixel density. So, she'd have a squirrel face, say, 6" tall on a 9x14 print, and I'd have a squirrel face 6" tall on a 20x28 print. So, it's really a complicated comparison when we change formats on real cameras that have different sensors with different pixel densities.

And then the different shape of the format also has implications. If you are normally interested in the long dimensions (such as those who do panoramics), 24x36 will capture more of the scene compared to 33x44 than if you are interested mostly in the narrow dimension. If you normally frame to standard photographic print sizes (8x10, 11x14, 16x20, 20x28, etc.), you'll be more interested in the narrow dimension. If you only show pictures on the internet or on a 16x9 monitor, you may not care or you may be more interested in the long dimension.

Focal length controls the magnification in the camera, while the format (sensor size, not density) controls how much of the scene will be recorded. Pixel density, sensor noise, and lens quality determine how much the image can be enlarged (i.e., magnification outside the camera).

The common method of comparison is to look at the length of the lens as a ratio to the diameter of the format. The diameter of 24x36 is 43mm, and the diameter of 33x44 is 55mm. 55/43=1.28. So, on a 645z, a 400 is 7.3 times the format diameter, and on a 24x36 camera, 43 times 7.3 is 314. But there's far more to the comparison than that.

Rick "answering a much larger question than the one you asked, but having his own preferred way of explaining it" Denney
Thks the comprehensive explanation....very useful.....will have to mull over the likely frequency of use of 300mm vs 400mm before I decide!
06-11-2018, 09:54 AM   #10
Junior Member




Join Date: Mar 2016
Posts: 32
Hi, I have the 400mm and I love it. I agree with most of what has been said about it here. Thanks for doing this test.
The bokeh can look a little janky at times.

I got the 2x tele-extender when I got my copy of the lens and now I'm trying to sell it. I just can't really get sharp results with it. I am actually better off just cropping into the regular 400mm files than using the 2x. Maybe I just got a bad copy of the 2x, I dunno. I am looking forward to trying the 1.4x.

Last edited by Irie; 06-11-2018 at 10:47 AM.
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!
645d, 645z, bokeh, camera, center, extender, f/5.6, focus, lens, lens test, medium format, scene, test
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: Now w/Test Pics - SMC Pentax-A* 645 600mm F5.6 ED [IF] w/Caps & 128mm SMC PF Filter darylk Sold Items 23 05-29-2018 09:59 AM
different between Pentax 6x7 300 F4 ED(IF) and 645 300 F4 ED(IF) popkrab Pentax Medium Format 9 12-17-2011 05:46 PM



All times are GMT -7. The time now is 08:34 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