800 PF Sharpness

Vermillion · Jul 11, 2025

I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Mid-frame examples were taken at the top right crossing lines in the rule of thirds grid

Now I'm wondering if something may be wrong with my 800 PF, since from what I can find online, specifically the tests on Photographylife, they should be much closer in terms of sharpness. In their test, the 800 PF actually was sharper in the Mid-frame and corner.

Would be interesting to see if someone else owns both lenses and is willing to compare them similarly.

shuncheung · Jul 11, 2025

Vermillion said:
I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

I do own both of those lenses, and they are both sharp, but I am not sure it is fair to compare a 400mm to a 800mm, at different distances. To me, there could be some camera/lens shake in your 800mm images. You need a large and sturdy tripod and head for such a long lens.

Since you are shooting indoors, I would redo the test with an electronic flash as the only source of light. That should eliminate all camera shake issues.

Vermillion · Jul 11, 2025

shuncheung said:
Vermillion said:

I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Click to expand...

I do own both of those lenses, and they are both sharp, but I am not sure it is fair to compare a 400mm to a 800mm, at different distances. To me, there could be some camera/lens shake in your 800mm images. You need a large and sturdy tripod and head for such a long lens.

Since you are shooting indoors, I would redo the test with an electronic flash as the only source of light. That should eliminate all camera shake issues.

I'm pretty sure there's no shake, as I used a sturdy tripod and remotely shot the images using snapbridge, but using a flash sounds like a good idea, I'll try that and see if there's a difference.

chambeshi · Jul 11, 2025

Timely release

Vermillion · Jul 11, 2025

Same story with flash:

I either hit the jackpot with that 400 f4.5 S, or my 800 PF is below average. There's definitely no shake at all this time, same settings without flash was a pitch black image.

Pierre Lagarde · Jul 11, 2025

Vermillion said:
I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Mid-frame examples were taken at the top right crossing lines in the rule of thirds grid

Now I'm wondering if something may be wrong with my 800 PF, since from what I can find online, specifically the tests on Photographylife, they should be much closer in terms of sharpness. In their test, the 800 PF actually was sharper in the Mid-frame and corner.

Would be interesting to see if someone else owns both lenses and is willing to compare them similarly.

In these shots, what are the distances between camera and target with both 400mm and 800mm (I mean, each for each, as you say you moved to have the same framing, which can be understood) ?

shuncheung · Jul 11, 2025

Pierre Lagarde said:
Vermillion said:

I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Mid-frame examples were taken at the top right crossing lines in the rule of thirds grid

Now I'm wondering if something may be wrong with my 800 PF, since from what I can find online, specifically the tests on Photographylife, they should be much closer in terms of sharpness. In their test, the 800 PF actually was sharper in the Mid-frame and corner.

Would be interesting to see if someone else owns both lenses and is willing to compare them similarly.

Click to expand...

In these shots, what are the distances between camera and target with both 400mm and 800mm (I mean, each for each, as you say you moved to have the same framing, which can be understood) ?

The OP has spelled out the distances from the target for the respective lenses. See the original post.

Pierre Lagarde · Jul 11, 2025

shuncheung said:
Pierre Lagarde said:

Vermillion said:

I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Mid-frame examples were taken at the top right crossing lines in the rule of thirds grid

Now I'm wondering if something may be wrong with my 800 PF, since from what I can find online, specifically the tests on Photographylife, they should be much closer in terms of sharpness. In their test, the 800 PF actually was sharper in the Mid-frame and corner.

Would be interesting to see if someone else owns both lenses and is willing to compare them similarly.

Click to expand...

In these shots, what are the distances between camera and target with both 400mm and 800mm (I mean, each for each, as you say you moved to have the same framing, which can be understood) ?

Click to expand...

The OP has spelled out the distances from the target for the respective lenses. See the original post.

That's not what I'm asking for, I'm asking for the exact distance, in meters, not the estimated one. It can be found in the exifs data I think. It's just a first question for further investigation. I may have been more specific.

The idea is to check if the camera measured the same that what the OP estimated.

bsinc1962 · Jul 11, 2025

Curious about what iso the two lenses are shot at if shooting indoors. The 400 is a f/4.5 and the 800 is f/6.3

there's no exif data listed

Pierre Lagarde · Jul 11, 2025

Vermillion said:
I've used the 800 PF for about two years now, and I've been very happy with it, but I recently picked up the 400 f4.5, and in direct comparison, the 800 PF just looks very soft.

Everything was shot from a tripod indoors, using Snapbridge to eliminate all shake. The 400mm lens at about 4m distance, the 800 PF at about 8m. Multiple shots were taken, these are the sharpest.

Mid-frame examples were taken at the top right crossing lines in the rule of thirds grid

Now I'm wondering if something may be wrong with my 800 PF, since from what I can find online, specifically the tests on Photographylife, they should be much closer in terms of sharpness. In their test, the 800 PF actually was sharper in the Mid-frame and corner.

Would be interesting to see if someone else owns both lenses and is willing to compare them similarly.

Following the remarks from bsinc1962 and shuncheung, maybe the simple thing is to provide each file with exifs. That way, everyone could check if any other difference can explain what is seen in your test shots (such as minimal distance, camera focusing differently in each shot , etc..)

Another point to check could be the way your raw processing software is managing sharpness for each lens, and so the resulting settings in it.

Bill Ferris · Jul 11, 2025

A sharpness comparison with the lenses at different distances from the target invalidates the results. A proper test will have the camera/lens on a tripod at a fixed distance from the subject. The shorter lens can be cropped or TC'd to match the angle of view of the longer lens.

I'd recommend shooting both lenses wide open at the same shutter speed with ISO adjusted to give all photos the same lightness.

If you do that test, you'll find the 800PF to be sharper. It will also be less noisy in low light.

If you object to comparing the lenses at the same distance because you can usually get close enough to subjects to fill the 400's frame, I'd recommend selling the 800 PF. You don't need the additional reach, the 400mm f/4.5 has a much shorter minimum focus distance, and it's faster when the frame is filled.

BasilG · Jul 11, 2025

Vermillion said:
Same story with flash:

I either hit the jackpot with that 400 f4.5 S, or my 800 PF is below average. There's definitely no shake at all this time, same settings without flash was a pitch black image.

Any chance you can increase the subject distance a bit? Maybe the two lenses behave differently at close range (though I think you are testing at a similar distance as PL).

shuncheung · Jul 11, 2025

Pierre Lagarde said:
Following the remarks from bsinc1962 and shuncheung, maybe the simple thing is to provide each file with exifs. That way, everyone could check if any other difference can explain what is seen in your test shots (such as minimal distance, camera focusing differently in each shot , etc..)

Another point to check could be the way your raw processing software is managing sharpness for each lens, and so the resulting settings in it.

I think the main question is whether the OP's particular sample of the 800mm/f6.3 PF is as sharp as other samples of that lens. I am afraid that the only way to find out is for the OP to borrow/rent another 800mm/f6.3 PF or two and test them side by side, or the OP needs to send his/her lens to someone else to compare.

Personally, I am very happy with the sharpness from my 800mm/f6.3 PF for field use, compared to lenses such as the 600mm/f6.3 PF and 600mm/f4 TC with and without the TC engaged. I am fine as long as I can capture satisfactory images in actual usage. The main selling point for the 800 PF is its relatively light weight and compact size (for a 800mm), thus I can take it to more destinations. That is why I am not particularly interested in shooting test charts.

Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

BasilG · Jul 11, 2025

Bill Ferris said:
A sharpness comparison with the lenses at different distances from the target invalidates the results.

No.

Bill Ferris said:
A proper test will have the camera/lens on a tripod at a fixed distance from the subject. The shorter lens can be cropped or TC'd to match the angle of view of the longer lens.

It depends on what you want to test. If you want to test the quality of the lens, the OP's approach is correct. If you want to test how much detail you can resolve on a subject at a given distance, your approach will tell you that. Neither is "right" or "wrong" - the two approaches just answer different questions.

BasilG · Jul 11, 2025

shuncheung said:
Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

600 PF is sharper than 400/4.5. So - not a general rule.

Pierre Lagarde · Jul 11, 2025

shuncheung said:
Pierre Lagarde said:

Following the remarks from bsinc1962 and shuncheung, maybe the simple thing is to provide each file with exifs. That way, everyone could check if any other difference can explain what is seen in your test shots (such as minimal distance, camera focusing differently in each shot , etc..)

Another point to check could be the way your raw processing software is managing sharpness for each lens, and so the resulting settings in it.

Click to expand...

I think the main question is whether the OP's particular sample of the 800mm/f6.3 PF is as sharp as other samples of that lens. I am afraid that the only way to find out is for the OP to borrow/rent another 800mm/f6.3 PF or two and test them side by side, or the OP needs to send his/her lens to someone else to compare.

Personally, I am very happy with the sharpness from my 800mm/f6.3 PF for field use, compared to lenses such as the 600mm/f6.3 PF and 600mm/f4 TC with and without the TC engaged. I am fine as long as I can capture satisfactory images in actual usage. The main selling point for the 800 PF is its relatively light weight and compact size (for a 800mm), thus I can take it to more destinations. That is why I am not particularly interested in shooting test charts.

Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

... or maybe there's a problems with the tests that we can see while looking at the exifs before trying to find another lens.

To my sense, the important sentence in OP's post is "I've used the 800 PF for about two years now, and I've been very happy with it". So it's fair to suspect something is wrong with the test, not with the lens, or at least to check a bit before conclude about the lens being faulty.

BTW, the 400mm F/4.5 is very precise and sharp, and self-testing (I mean mine too) can lead to different results from those processed in laboratories that are well versed in the exercise and have the right equipment and fine-tuned settings.

I would never recommend to anybody to make sharpness tests if they are "very happy" with a lens, anyway.

shuncheung · Jul 11, 2025

Pierre Lagarde said:
shuncheung said:

Pierre Lagarde said:

Following the remarks from bsinc1962 and shuncheung, maybe the simple thing is to provide each file with exifs. That way, everyone could check if any other difference can explain what is seen in your test shots (such as minimal distance, camera focusing differently in each shot , etc..)

Another point to check could be the way your raw processing software is managing sharpness for each lens, and so the resulting settings in it.

Click to expand...

I think the main question is whether the OP's particular sample of the 800mm/f6.3 PF is as sharp as other samples of that lens. I am afraid that the only way to find out is for the OP to borrow/rent another 800mm/f6.3 PF or two and test them side by side, or the OP needs to send his/her lens to someone else to compare.

Personally, I am very happy with the sharpness from my 800mm/f6.3 PF for field use, compared to lenses such as the 600mm/f6.3 PF and 600mm/f4 TC with and without the TC engaged. I am fine as long as I can capture satisfactory images in actual usage. The main selling point for the 800 PF is its relatively light weight and compact size (for a 800mm), thus I can take it to more destinations. That is why I am not particularly interested in shooting test charts.

Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

Click to expand...

... or maybe there's a problems with the tests that we can see while looking at the exifs before trying to find another lens.

To my sense, the important sentence in OP's post is "I've used the 800 PF for about two years now, and I've been very happy with it". So it's fair to suspect something is wrong with the test, not with the lens, or at least to check a bit before conclude about the lens being faulty.

That is exactly my point. If the OP has been very happy with that particular 800mm PF for 2 years, why waste time testing it indoors and compare it to another lens with a totally different focal length, 400mm vs. 800mm, and at different distances?

Pierre Lagarde said:
BTW, the 400mm F/4.5 is very precise and sharp, and self-testing (I mean mine too) can lead to different results from those processed in laboratories that are well versed in the exercise and have the right equipment and fine-tuned settings.

I would never recommend to anybody to make sharpness tests if they are "very happy" with a lens, anyway.

shuncheung · Jul 11, 2025

BasilG said:
shuncheung said:

Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

Click to expand...

600 PF is sharper than 400/4.5. So - not a general rule.

What is the basis for your conclusion that the 600 PF is sharper than the 400mm/f4.5?

I happen to have both of those two lenses, and they both give me excellent results in the field. That is all I care about. However, my usages for 400mm and 600mm are fairly different.

Pierre Lagarde · Jul 11, 2025

shuncheung said:
Pierre Lagarde said:

shuncheung said:

Pierre Lagarde said:

Following the remarks from bsinc1962 and shuncheung, maybe the simple thing is to provide each file with exifs. That way, everyone could check if any other difference can explain what is seen in your test shots (such as minimal distance, camera focusing differently in each shot , etc..)

Another point to check could be the way your raw processing software is managing sharpness for each lens, and so the resulting settings in it.

Click to expand...

I think the main question is whether the OP's particular sample of the 800mm/f6.3 PF is as sharp as other samples of that lens. I am afraid that the only way to find out is for the OP to borrow/rent another 800mm/f6.3 PF or two and test them side by side, or the OP needs to send his/her lens to someone else to compare.

Personally, I am very happy with the sharpness from my 800mm/f6.3 PF for field use, compared to lenses such as the 600mm/f6.3 PF and 600mm/f4 TC with and without the TC engaged. I am fine as long as I can capture satisfactory images in actual usage. The main selling point for the 800 PF is its relatively light weight and compact size (for a 800mm), thus I can take it to more destinations. That is why I am not particularly interested in shooting test charts.

Generally speaking, I am not particularly surprised that a 400mm lens is sharper than a 800mm, and a lens with conventional lens elements is sharper than PF lenses.

Click to expand...

... or maybe there's a problems with the tests that we can see while looking at the exifs before trying to find another lens.

To my sense, the important sentence in OP's post is "I've used the 800 PF for about two years now, and I've been very happy with it". So it's fair to suspect something is wrong with the test, not with the lens, or at least to check a bit before conclude about the lens being faulty.

Click to expand...

That is exactly my point. If the OP has been very happy with that particular 800mm PF for 2 years, why waste time testing it indoors and compare it to another lens with a totally different focal length, 400mm vs. 800mm, and at different distances?

Fair, we agree... + chances are he would be even more happy with the 400mm F/4.5

Vermillion · Jul 11, 2025

Bill Ferris said:
A sharpness comparison with the lenses at different distances from the target invalidates the results. A proper test will have the camera/lens on a tripod at a fixed distance from the subject. The shorter lens can be cropped or TC'd to match the angle of view of the longer lens.

I'd recommend shooting both lenses wide open at the same shutter speed with ISO adjusted to give all photos the same lightness.

If you do that test, you'll find the 800PF to be sharper. It will also be less noisy in low light.

If you object to comparing the lenses at the same distance because you can usually get close enough to subjects to fill the 400's frame, I'd recommend selling the 800 PF. You don't need the additional reach, the 400mm f/4.5 has a much shorter minimum focus distance, and it's faster when the frame is filled.

That makes no sense, I'm testing the lenses' sharpness, not looking for real world results. You always equalize subject size, that's why test chart shots always show the full test chart.

Anyway, here are the two RAW files for the shots from of the centre:

800mm - 7.38m

https://mega.nz/file/rBlySTAD#Nk-v0PwBHsixN19lyr2sgIamMuww1uCtgs9EiNRGvvg

400mm - 3.78m

https://mega.nz/file/7QlhlaCb#eW00f8ObzcssuILsXpWXChTmSU-cq1hhEyXZnb61iZg

Tried countless times, even manually focusing with maximum magnification, with and without VR, this is as sharp as the 800 PF gets in the centre.

shuncheung said:
That is exactly my point. If the OP has been very happy with that particular 800mm PF for 2 years, why waste time testing it indoors and compare it to another lens with a totally different focal length, 400mm vs. 800mm, and at different distances?

I totally understand that. I was just curious about how they'd stack up, and ended up being shocked by how soft the 800 PF looks in comparison. I am aware that the 800 PF will deliver superior image when shooting from the same distance, and I bought the 400 f4.5 specifically for closer encounters, like shore birds.

800 PF Sharpness

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