[swanlefitte]

I forgot the primary reason I use it and I had just taken an image on friday.

reason 5 to get focus on the eye instead of a branch. The bigger the eye is, the easier it is. It is still not easy when the bird is moving around and the branches are not, especially when you are standing on uneven ground in marsh and have to crouch to get through the branches in the first place.

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Last edited by swanlefitte; 06-14-2022 at 12:43 PM.

[swanlefitte]

Here is a noise comparison. I used the dpreview images from the k1 and k50 because they have the same pixel density. The k1 at ISO 1600 and k50 at both ISO 1600 and ISO 800

You can see at 100% the noise is about the same at ISO 1600 but the k1 image is much bigger. The k50 at ISO 800 is better and smaller. But when you enlarge it 1.5x so you view at the same size the noise advantage is gone. You do not really lose a stop of light.

alternatively I could resize the k1 image down to look like the k50 800 noise level. (Sorry I labeled the photo as K5 but it is K50)

[jjdgti]

Is there any rumor or plan from Ricoh to remake the 1.7 AF Adapter with the new HD coatings. Maybe with HSM motor included?

I love this Pentax F 1.7 AF Adapter because it allow me to use manual lenses (fast primes) as Autofocus. I use it with my 50mm 1.2 to mimic the 85mm 2.0 focal length.

[Sandy Hancock]

This one was taken with 150-450mm +HD Pentax-DA 1.4x AW AF Rear Converter : White wagtail | Hatsofe B | Flickr
These are aproximately the same size objects , under bright sunlight and from a similar distance.

Thanks.
Stationary bird vs walking bird: pretty hard to compare critically even at that shutter speed. I wonder if the latter is slightly front focussed, but it still looks pretty good at that size.

[csa]

Just purchased a new HD 1.4 TC from a great member here! Excited to try it with my 55-300 PLM!

[hatsofe]

Thanks.
Stationary bird vs walking bird: pretty hard to compare critically even at that shutter speed. I wonder if the latter is slightly front focussed, but it still looks pretty good at that size.

This bird never remains stationary ,you probably have never seen it in nature! The other bird was moving faster, of course but the image was not smudged. It is the lack of tiny details, lines, dots and softer all-together picture bother me. I noticed, that the same 1.4x modern convertor performed very well with lower focal length optics, like 50mm, 150mm and 200mm. Here is another examples with and without this convertor on 150-450mm.
No convertor: Glossy ibis | Hatsofe B | Flickr
W/convertor:Shag. | Hatsofe B | Flickr
I recall that the post-processing also was more complicated and longer with the images made with the convertor on.

[clackers]

Its 1 to 1 comparison
Ya simple math gets it wrong all the time, Half the density of light over a area that is 2 times larger is not equal to twice the density of light over an area 1/2 of its size
0.5 X 2 = 2 X 0.5
1=1

?

Get a K-30 and a K-1 at f4, 1/1000s, ISO 100.

Put a 1.4 TC on the K-1 and it's now underexposed by fifty percent.

That's it. There's no free lunch.

Individual pixels never know if they are part of a full frame or an APS-C one.

Every RAW image file is just a spreadsheet of pixel values.

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Last edited by clackers; 06-16-2022 at 12:10 AM.

[Ian Stuart Forsyth]

Every RAW image file is just a spreadsheet of pixel values.

Yes those pixels represent values but over a volume of pixels, what happens of that pixel represent 1 in 15mp or 1 in 36mp

If that pixel represents 1 in 36mp how it appears and how the noise appears will be much lower than if that pixel represents 1 in 15mp, the 1 in 15 would have a greater influence as to how that noise will appear the final image

It was no different with film how much influence a film grain had to how the final image looked was dependent on the volume of grains it is being compared to. The more units it is being compared to the less influence that single value represents.

We can have a PGI ( Print grain index) below the threshold so no grain can be detectable ( below 25) using a 4x5 camera whereas using 135 that very same film with the very same grain size ( pixel size) that will show a much higher PGI and degrade the image much more than what was happening to the 4x5 print

[weverka]

If your lens has better resolution than the pixel size of your sensor, adding a teleconverter helps. It magnifies the image.
Otherwise, just tell your ff camera to crop, or crop in post.

Crop and teleconverter give you the same total light, since the latter just takes what would have been the cropped area and spreads the same light over a full frame.

[swanlefitte]

?

There's no free lunch.

Yes you can trade 1 stop of light for 1 stop of pixels. Do you want a larger size or a brighter smaller picture. They are the same. That smaller brighter photp will lose at the bigger size. That bigger size will gain brightness at a smaller size. or the trade off of noise by amplifying the light as you shrink the photo.

[Ian Stuart Forsyth]

This image was made with 150-450mm only : Graceful Prinia | Hatsofe B | Flickr
This one was taken with 150-450mm +HD Pentax-DA 1.4x AW AF Rear Converter : White wagtail | Hatsofe B | Flickr
These are aproximately the same size objects , under bright sunlight and from a similar distance.

One of the problems you are having is that the photo is not focused on the bird for the one with the TC

[hatsofe]

One of the problems you are having is that the photo is not focused on the bird for the one with the TC

I checked the RAW file again . The bird in the picture made with this convertor is within the depth of field. This convertor coupled with 150-450mm turns any bright tiny details into blurred spots which simply merge and create large ones and micro contrast adjustment in post processing become useless. It also leaves no details but a noise in shadows. The only way out of this is a well illuminated scene.

[Ian Stuart Forsyth]

The bird in the picture made with this convertor is within the depth of field.

The DOF is shallower and there is no problem with the detail in the rock found in front of the the bird which would lead me to believe that it is an issue with the placement of the focus plane