[Lowell Goudge]

This is the "fallout" from another thread where I challenged the owner of an SMC-A 70-210 F4 with my Vivitar S1 70-210 F3.5 to a shoot out to see which lens is better. The idea is to pick typical photos that anyone can take, therefore since neither of us own both lenses, we could take comparative photos.

My initial proposed rules were based upon just the two of us, but it has been suggested to make it a general challenge, open to more people,

My initial rules were:


One of us proposes a subject, - pets, flowers birds etc. each in sequence, and takes a shot that they feel demonstrates the qualities of the lens, and the other has to shoot under the same conditions (or as close as possible) and we judge based upon the full frame (but resized to post) plus 2 ~10%crops, one center one corner.

I suggest either 6 or 10MP camera as I have an *istD and K10D.

Propose with and without flash if you can do it.
Propose min, max and middle focal length and a similar mix of subject distances, plus macro

The first comment back in the pther forum, which may help a little in guidance is linked below.

https://www.pentaxforums.com/forums/401199-post48.html

[Jimfear]

Would shots taken with film cameras be allowed? I think it could be of some interest regarding border sharpness?

[Lowell Goudge]

Would shots taken with film cameras be allowed? I think it could be of some interest regarding border sharpness?

I guess I had not thought this all the way through, but yes, we cold possibly accomodate this, perhaps 3 sample sections center10% corner 10% ASP-C sensor, and for film shooters, similar size at scanned resolution out of the corner.


I guess I might need to dust off my PZ-1 for some of this. I propose minimum scan resolution of 2880 pixels per inch, since that is what my scanner can do.

[Steinback]

Lowell, sounds like you and Jimfear could get this started on film without too much trouble. Besides deciding on a film type that both of you can get and a scanning resolution, do you need anything other than subjects?

Jimfear, how do you scan your photos?

I can't really see using any retouching, other than perhaps trying to match the scanned image's colours to the print (which would have to be agreed upon ahead of time).

[Jimfear]

I scan my photos with an Epson V700 at any resolution up to 6400dpi.

What kind of subject should it be? Some kind of "controlled" setup indoors, or real life situation outside? What do you think?

Retouching is a difficult question as different scanners have different sharpness and you usually have to add a little sharpness to get the most out of your scan.

[Class A]

Which zooms (focal length range) do you want to admit?

[Steinback]

I'm going to copy and paste in my relevant comments from the other thread where we were discussing this, just so they are in the same place:

A photo duel sounds like it would make for a fun thread. I could see it spawning a series of face offs, but choosing 1 focal range to start with is probably the way to go.

If you want to start in the ~80-200 range, I believe that I have the same Vivitar Series 1 70-210 f/3.5 (1st version) that you do, and there are lots of others around here with later versions of the series 1. You/we just have to find a couple of people with an A70-210 f/4, M or K 80-200 f/4.5, or possibly an FA 80-200 f/2.8 willing to step up and participate.

Possible limiting the field to constant aperture zooms that cover 80-200mm (so in theory a 60-250 f/4 or Sigma 70-200 f/2.8 would qualify, but a 50-135 or 50-150 wouldn't) would be somewhere to start. I would be fine with shooting my K10 set at 6mp if you want the same approximate resolution from any/all bodies being used.

Restricting the field to just 2 lenses would be another option and might be easier to manage but the trade off is that it would cut down on the number of people able to participate.

Photos probably ought to be of things that an average person could find in their neighbourhood or house, regardless of where in the world they live (fork, coin approximately 1 inch across, stop sign, house, etc.?).

[Steinback]

To expand on what I quoted above my thought with suggesting that any constant aperture zoom that covers the range of 80-200 could enter the comparison was that we could choose, say, 3 focal lengths in that range for people to compare.

For example if we chose 80, 140, and 200 mm then people could take a few photos at each focal length at close focus, medium distance and infinity focus, for a total of 9 photos. I'm not sure what apertures people want to use, but something like f/4 and f/8 for each image at whatever shutter speed is required to use those apertures would take us up to 18 images.

I don't have a problem with shooting more, but keeping it inside 1 or 2 rolls of film would keep costs down and help to keep the number of different setups and shots people are making (on film or digital) a manageable number.

In terms of film I've usually been shooting Fuji Superia 400 because it is relatively inexpensive and readily available where I live, what do other people have around?

[Lowell Goudge]

To expand on what I quoted above my thought with suggesting that any constant aperture zoom that covers the range of 80-200 could enter the comparison was that we could choose, say, 3 focal lengths in that range for people to compare.

agreed

For example if we chose 80, 140, and 200 mm then people could take a few photos at each focal length at close focus, medium distance and infinity focus, for a total of 9 photos. I'm not sure what apertures people want to use, but something like f/4 and f/8 for each image at whatever shutter speed is required to use those apertures would take us up to 18 images.

I don't have a problem with shooting more, but keeping it inside 1 or 2 rolls of film would keep costs down and help to keep the number of different setups and shots people are making (on film or digital) a manageable number.

In terms of film I've usually been shooting Fuji Superia 400 because it is relatively inexpensive and readily available where I live, what do other people have around?

for images I can understand film will be expensive, I had not thought about this, as I shoot mostly digital now.

I think we could simply cut things down to maximum apature and F8 for shots, and then the 3 focla lengths gets idt down to 6 shots.

[audiobomber]

For example if we chose 80, 140, and 200 mm then people could take a few photos at each focal length at close focus, medium distance and infinity focus, for a total of 9 photos. I'm not sure what apertures people want to use, but something like f/4 and f/8 for each image at whatever shutter speed is required to use those apertures would take us up to 18 images.

The DA 55-300mm is f/4.5 below 210mm. It would be interesting to see how it compares.

[Fl_Gulfer]

I have a Ricoh "P" 70-210 f3.9

[Blue]

I have a Tamron SP 70-210mm adaptall-2 model 52A.

[arpaagent]

I'd be willing to offer some competition coming from and SMC Pentax-A 70-210/4 zoom on my K200D. It's in excellent condition so should be a good representation of the IQ for the lens.

One other thing to note: The rules would also have to include some sort of specification on how to post process the files, or to shoot in JPEG with certain settings. Wouldn't want someone sharpening it in software more than others since that would create an uneven playing field.

Let me know what our subjects will be and hopefully I could find something suitable.

[audiobomber]

6mp is not enough resolution for lens comparisons.

[FHPhotographer]

6mp is not enough resolution for lens comparisons.

I don't see why not. Perhaps there's something I'm missing about the term resolution.

I thought the general guide was: higher pixel density = lower image quality.So a K100 with 1.7 MP/cm² pixel density should give better image quality than a K200 at 2.8 MP/cm² pixel density at say a 3x5" 100% crop.

Or am I confusing terms again,
Brian