FA* 645 300mm f/4 ED IF or 400mm F/5.6 SMC FA ED IF

**cdd29** · 10-18-2021, 06:47 PM

I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom.

**DonV** · 10-18-2021, 08:31 PM

I find the 400mm to be an excellent lens- it is really sharp "enough".

300mm is just not long enough if you already have the 150-300. JMHO.

**TDvN57** · 10-18-2021, 11:02 PM

In my experience the 150-300mm, 400mm and 300mm are equal in sharpness for all practical purposes.

FA 400mm
A picture looking up into a tree to get a picture with a brighter sky in the background will give fringing with the 400mm. Almost impossible to remove the fringing. You can change it's color in editing but it will be visible.

The 400mm does not pair very well with the teleconverters.

I found the 400mm to be as sharp as the 300mm when it comes to resolving small details at a distance.

FA* 300mm f4
In a side-by-side test with the 400mm, in similar conditions I could not see fringing with the 300mm.

It pairs very well with the teleconverters, especially the TC1.4.

FA 150-300mm
The 150-300mm is a fantastic lightweight lens but that is it, don't expect to stretch its focal length with a teleconverter. I can't remember if it has a fringing problem. If it does I have not come across it in my pictures.

In terms of sharpness I also found the 150-300mm to be just as sharp as the 300mm FA*.

Andrea K · 10-19-2021, 01:56 AM

Buy the 300* and the 1.4x TC

**RICHARD L.** · 10-19-2021, 04:00 AM

The image below was taken with the FA 400 mm tripod-mounted : great resistance to ghosting and excellent sharpness @ f/16.

The 2 following images were taken with the FA 150-300 mm zoom tripod-mounted : excellent uniform sharpness and resolution @ f/11 (upper at 300 mm, lower at 150 mm).

The following image was taken with the FA* 300 mm f/4 on tripod @ f/11 : excellent uniform sharpness.

Magnification of the lower part of an FA 400 mm f/5.6 picture below : resolution of far-away fine details is astounding.

Whatever your final choice is, these 3 lenses are all excellent for landscape pictures. All require solid support (tripod) and middle apertures to perform at their best. If you already have the FA 150-300 mm zoom, the FA* 300 mm f/4 is expensive, marginally faster, not very good wide-open and has about the same resolution (maybe less CA like Theuns mentionned). The FA 400 mm sells usually for a good price, so I would consider this choice first.

Regards

**rdenney** · 10-22-2021, 10:16 AM

Originally posted by Andrea K

Buy the 300* and the 1.4x TC

This is fine but not better according to my testing:

https://www.pentaxforums.com/forums/48-pentax-medium-format/366440-grand-len...ml#post4300023

But it is more flexible for a given space in the pack.

Rick "sample variation disclaimer goes here" Denney

Andrea K · 10-23-2021, 06:17 AM

Sure, the advice is to have more flexibility.

I don't own the FA 645 400mm ( at the moment...) but this was an old test about the FA* 645 300mm with RC, I used the K-1.

The FOV with the FA 50mm f/1,4:

The FA* 645 300mm FOV

Now some crops enlarged to match the subject's size. All shots with the lens at f/5,6
300mm + RC 2X 100%:

300mm + RC 1,4X 147%:

300mm 200%:

Last edited by Andrea K; 10-23-2021 at 07:25 AM.

angerdan · 10-25-2021, 04:13 PM - **1 Like**

Originally posted by cdd29

I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom.

There's a useful table in this thread, where several 645 lenses are rated:
645 Lens Tests - Identifying the top performers - Again - PentaxForums.com

mikeSF · 11-05-2021, 08:44 AM

Originally posted by cdd29

I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom.

Don't forget the 67 M*300/4. I use that for my 300mm range and it is big but super sharp.
SMC Pentax-M* 67 300mm F4 ED [IF] Reviews - 67 Telephoto Primes - Pentax Lens Reviews & Lens Database

here is my album using that lens on 645D and 645Z bodies: Lens: 67 M*300 f/4 | Flickr

**Ed Hurst** · 11-05-2021, 01:56 PM - **1 Like**

Agree Mike. That lens is, in my experience, the sharpest option (though big, of course).

10-18-2021, 06:47 PM	#1
cdd29 Loyal Site Supporter Join Date: Sep 2016 Location: Southern Indiana Photos: Gallery Posts: 961	*FA 645 300mm f/4 ED IF or 400mm F/5.6 SMC FA ED IF** I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom.

10-19-2021, 04:00 AM	#5
RICHARD L. Loyal Site Supporter Join Date: Oct 2018 Location: Quebec City, Quebec Posts: 6,582	*Comparing FA 400 mm f/5.6, FA 150-300 mm f/5.6 zoom and FA 300 mm f/4 on 645Z The image below was taken with the FA 400 mm tripod-mounted : great resistance to ghosting and excellent sharpness @ f/16. The 2 following images were taken with the FA 150-300 mm zoom tripod-mounted : excellent uniform sharpness and resolution @ f/11 (upper at 300 mm, lower at 150 mm). The following image was taken with the FA* 300 mm f/4 on tripod @ f/11 : excellent uniform sharpness. Magnification of the lower part of an FA 400 mm f/5.6 picture below : resolution of far-away fine details is astounding.** Whatever your final choice is, these 3 lenses are all excellent for landscape pictures. All require solid support (tripod) and middle apertures to perform at their best. If you already have the FA 150-300 mm zoom, the FA* 300 mm f/4 is expensive, marginally faster, not very good wide-open and has about the same resolution (maybe less CA like Theuns mentionned). The FA 400 mm sells usually for a good price, so I would consider this choice first. Regards Last edited by RICHARD L.; 10-19-2021 at 08:10 AM.

10-22-2021, 10:16 AM	#6
rdenney Site Supporter Join Date: Feb 2018 Location: NoVA Posts: 635	Originally posted by Andrea K Buy the 300* and the 1.4x TC This is fine but not better according to my testing: https://www.pentaxforums.com/forums/48-pentax-medium-format/366440-grand-len...ml#post4300023 But it is more flexible for a given space in the pack. Rick "sample variation disclaimer goes here" Denney Last edited by rdenney; 10-22-2021 at 10:49 AM.

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10-18-2021, 08:31 PM	#2
DonV Site Supporter Join Date: Jan 2017 Location: Near Charlotte NC Photos: Albums Posts: 693	I find the 400mm to be an excellent lens- it is really sharp "enough". 300mm is just not long enough if you already have the 150-300. JMHO.

10-18-2021, 11:02 PM	#3
TDvN57 Loyal Site Supporter Join Date: Jul 2011 Location: Berlin Photos: Gallery Posts: 1,149	In my experience the 150-300mm, 400mm and 300mm are equal in sharpness for all practical purposes. FA 400mm A picture looking up into a tree to get a picture with a brighter sky in the background will give fringing with the 400mm. Almost impossible to remove the fringing. You can change it's color in editing but it will be visible. The 400mm does not pair very well with the teleconverters. I found the 400mm to be as sharp as the 300mm when it comes to resolving small details at a distance. FA* 300mm f4 In a side-by-side test with the 400mm, in similar conditions I could not see fringing with the 300mm. It pairs very well with the teleconverters, especially the TC1.4. FA 150-300mm The 150-300mm is a fantastic lightweight lens but that is it, don't expect to stretch its focal length with a teleconverter. I can't remember if it has a fringing problem. If it does I have not come across it in my pictures. In terms of sharpness I also found the 150-300mm to be just as sharp as the 300mm FA*.

10-19-2021, 01:56 AM	#4
Andrea K Pentaxian Join Date: Mar 2009 Location: Rome, Italy Posts: 822	Buy the 300* and the 1.4x TC

10-23-2021, 06:17 AM	#7
Andrea K Pentaxian Join Date: Mar 2009 Location: Rome, Italy Posts: 822	Sure, the advice is to have more flexibility. I don't own the FA 645 400mm ( at the moment...) but this was an old test about the FA* 645 300mm with RC, I used the K-1. The FOV with the FA 50mm f/1,4: The FA* 645 300mm FOV Now some crops enlarged to match the subject's size. All shots with the lens at f/5,6 300mm + RC 2X 100%: 300mm + RC 1,4X 147%: 300mm 200%: Last edited by Andrea K; 10-23-2021 at 07:25 AM.

10-25-2021, 04:13 PM - 1 Like	#8
angerdan Pentaxian Join Date: Feb 2015 Photos: Gallery \| Albums Posts: 2,639	Originally posted by cdd29 I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom. There's a useful table in this thread, where several 645 lenses are rated: 645 Lens Tests - Identifying the top performers - Again - PentaxForums.com

11-05-2021, 08:44 AM	#9
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	Originally posted by cdd29 I've bought stuff for my other systems but no love for the 645z, so toying with getting a new long prime. Like the longer 400, but heard the 300 is a sharper lens. What are the ins and outs of these? Personal experience? Ultimately would replace a 150-300mm zoom. Don't forget the 67 M300/4. I use that for my 300mm range and it is big but super sharp. SMC Pentax-M 67 300mm F4 ED [IF] Reviews - 67 Telephoto Primes - Pentax Lens Reviews & Lens Database here is my album using that lens on 645D and 645Z bodies: Lens: 67 M*300 f/4 \| Flickr

11-05-2021, 01:56 PM - 1 Like	#10
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	Agree Mike. That lens is, in my experience, the sharpest option (though big, of course).